diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 4f6738f..654da64 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -27,11 +27,14 @@ jobs:
             esac
           done
       - name: Python compiles
-        run: python -m py_compile ui/*.py apk-catalog/*.py frame/android/*.py
+        run: |
+          python -m py_compile ui/*.py apk-catalog/*.py frame/android/*.py
+          # Valve's devkit-utils (vendored; run by the Frame's python3). Most have no .py suffix.
+          python -m py_compile $(find frame/devkit-utils -type f ! -name '*.*' ! -name LICENSE) frame/devkit-utils/devkit_utils/*.py
       - name: Server tests
         run: python -m unittest discover -s tests -v
       - name: App syntax
-        run: node --check app/main.js && node --check app/build/make-icon.js && node --check app/build/fetch-deps.js && node --check app/preload.js
+        run: node --check app/main.js && node --check app/build/make-icon.js && node --check app/build/fetch-deps.js && node --check app/preload.js && node --check app/install-link.js
 
   # The server runs on each desktop OS the app ships for, on the Python version
   # the app bundles (app/build/fetch-deps.js) and, on Ubuntu, a newer one.
diff --git a/README.md b/README.md
index 573e1ae..8be10f2 100644
--- a/README.md
+++ b/README.md
@@ -58,8 +58,8 @@ About 4,500 F-Droid apps rated for the Frame. One click installs each as its own
 <tr>
 <td valign="top">
 
-**📁 Files and clipboard**<br>
-Drag files onto the window to send them. Send text or your clipboard straight to the headset's desktop.
+**📁 Files, games and clipboard**<br>
+Drag files onto the window to send them. Drop a game's .zip, folder or .exe to add it to the Steam library, with Proton or the Linux runtime picked for you. Send text or your clipboard straight to the headset's desktop.
 
 </td>
 <td valign="top">
@@ -86,7 +86,8 @@ SSH, SFTP, Steam Link, remote desktop, volume, sleep, restart and shut down.
 </table>
 
 Nothing is installed on the Frame for any of this: the app uses what SteamOS
-already ships. [How each feature works](docs/frame-control.md).
+already ships (sideloading a game copies Valve's own devkit scripts to
+`~/devkit-utils`, as Valve's Devkit Client does). [How each feature works](docs/frame-control.md).
 
 ## Install
 
@@ -147,13 +148,21 @@ computer.
    Connection**, which finds the headset, creates an SSH key, and asks for that
    password once in a terminal window. If it can't find the Frame, type the
    IP address from the Frame's Quick Settings.
+
+   Before asking for the password it tries Valve's SteamOS devkit pairing: in
+   the headset, open Steam Settings → Developer → **Pair new host** and approve
+   the request, and no password is needed. (The service and the pairing-mode
+   step are verified on a Frame; the approval itself isn't yet. See
+   [SSH](docs/ssh.md#password-free-pairing-steamos-devkit-service).)
 3. That's it. The app now reaches the headset whenever it's awake and on the
    same network. For anywhere else, see [Tailscale](docs/tailscale.md).
 
 **What it changes:** only what you click. Installs go to your user account on
-the Frame (`--user` Flatpaks, Lepton instances, Steam downloads), and nothing
+the Frame (`--user` Flatpaks, Lepton instances, Steam downloads, sideloaded
+games in `~/devkit-game`), and nothing
 needs `sudo` except the power buttons. On your computer it adds a `Host frame`
-entry to `~/.ssh/config` and a key at `~/.ssh/id_ed25519_frame`.
+entry to `~/.ssh/config` and keys at `~/.ssh/id_ed25519_frame` and
+`~/.ssh/id_rsa_frame_devkit` (the pairing service only takes RSA keys).
 
 ## Feedback
 
@@ -177,6 +186,8 @@ Frame's software fits together, all checked against a real headset and labelled
 | [Scripts and headset setup](docs/scripts.md) | The command-line helpers, minimum typing, streaming options, floating panels |
 | [How the Frame works](docs/how-the-frame-works.md) | SteamVR → gamescope → Plasma, verified facts, debugging |
 | [Android apps (Lepton)](docs/apks.md) | Sideloading, the rated F-Droid catalogue, per-app instances |
+| [Sideloading Linux and Windows games](docs/sideloading.md) | A .zip, folder or .exe as a Steam Devkit Game, runtime detection |
+| [Install links for websites](docs/web-install.md) | `frame-control://install` links and manifests, the rules, a button to paste |
 | [Steam games](docs/steam-games.md) · [VR video](docs/vr-video.md) · [WebXR in Chromium](docs/webxr-chromium.md) | Installing and buying, watching VR180/360, the Chromium build |
 | [SSH](docs/ssh.md) · [Streaming](docs/streaming.md) · [Files](docs/file-transfer.md) · [Panels](docs/panels.md) · [Tailscale](docs/tailscale.md) | Topic notes |
 | [Open questions](docs/open-questions.md) | What's still unchecked |
diff --git a/app/install-link.js b/app/install-link.js
new file mode 100644
index 0000000..e64cce1
--- /dev/null
+++ b/app/install-link.js
@@ -0,0 +1,33 @@
+// Parses frame-control://install?manifest=URL and frame-control://install?url=URL
+// (see docs/web-install.md). Pure, so it runs under plain node for the tests.
+// This is only a first filter: ui/frame_webinstall.py applies the full URL rules
+// (HTTPS, no private addresses, redirects) before anything is fetched.
+const SCHEME = "frame-control";
+const MAX_LINK = 4096;
+const MAX_URL = 2048;
+
+// {kind: "manifest" | "url", target} or null if raw isn't a usable install link.
+function parseInstallLink(raw) {
+  if (typeof raw !== "string" || raw.length > MAX_LINK || !raw.toLowerCase().startsWith(`${SCHEME}:`)) return null;
+  let link;
+  try { link = new URL(raw); } catch { return null; }
+  // frame-control://install?… puts "install" in the host; accept a trailing slash too.
+  if (link.protocol !== `${SCHEME}:` || link.hostname !== "install" || !["", "/"].includes(link.pathname)) return null;
+  const keys = [...new Set(link.searchParams.keys())];
+  if (keys.length !== 1 || !["manifest", "url"].includes(keys[0])) return null;
+  const values = link.searchParams.getAll(keys[0]);
+  if (values.length !== 1) return null;
+  const target = values[0];
+  if (!target || target.length > MAX_URL) return null;
+  let parsed;
+  try { parsed = new URL(target); } catch { return null; }
+  if (!["https:", "http:"].includes(parsed.protocol) || parsed.username || parsed.password) return null;
+  return { kind: keys[0], target };
+}
+
+// The link among command-line arguments (Windows and Linux pass it there).
+function linkFromArgv(argv) {
+  return (argv || []).find((a) => typeof a === "string" && a.toLowerCase().startsWith(`${SCHEME}:`)) || null;
+}
+
+module.exports = { SCHEME, parseInstallLink, linkFromArgv };
diff --git a/app/main.js b/app/main.js
index 37e71f9..ad64d8f 100644
--- a/app/main.js
+++ b/app/main.js
@@ -9,6 +9,7 @@ const http = require("http");
 const net = require("net");
 const os = require("os");
 const path = require("path");
+const { SCHEME, parseInstallLink, linkFromArgv } = require("./install-link");
 
 const run = promisify(execFile);
 
@@ -233,14 +234,57 @@ async function firstRunCheck() {
   if (response === 0) setUpConnection();
 }
 
-ipcMain.handle("clipboard:read", (e) => {
-  if (!win || e.sender !== win.webContents || !url) return "";
+// IPC only from our own page in our own window.
+function fromUi(e) {
+  if (!win || e.sender !== win.webContents || !url || !e.senderFrame) return false;
   try {
-    if (new URL(e.senderFrame.url).origin !== new URL(url).origin) return "";
-  } catch { return ""; }
-  return clipboard.readText();
+    return new URL(e.senderFrame.url).origin === new URL(url).origin;
+  } catch { return false; }
+}
+
+ipcMain.handle("clipboard:read", (e) => fromUi(e) ? clipboard.readText() : "");
+
+// frame-control://install links from websites (docs/web-install.md). They can
+// arrive before the window or server exists (macOS open-url on a cold launch),
+// so they wait here until the page asks for them. The page checks the link with
+// the server and installs nothing until the user confirms in its dialog.
+const pendingLinks = [];
+let linkPage = null;  // the webContents whose current page is listening
+
+function openInstallLink(raw) {
+  const req = parseInstallLink(raw);
+  if (!req) {
+    app.whenReady().then(() => dialog.showErrorBox("Frame Control can't use this link",
+      "Install links look like frame-control://install?manifest=https://… or frame-control://install?url=https://…"));
+    return;
+  }
+  pendingLinks.push(req);
+  if (pendingLinks.length > 5) pendingLinks.shift();  // a page opening links in a loop
+  deliverLinks();
+  if (win) { if (win.isMinimized()) win.restore(); win.focus(); }
+}
+
+function deliverLinks() {
+  if (!win || !linkPage || linkPage !== win.webContents) return;
+  while (pendingLinks.length) win.webContents.send("install-link", pendingLinks.shift());
+}
+
+ipcMain.on("install-link:ready", (e) => {
+  if (!fromUi(e)) return;
+  linkPage = e.sender;
+  deliverLinks();
 });
 
+function registerScheme() {
+  // A checkout runs as `electron .`, so the OS must be told the script too.
+  // (macOS takes the scheme from Info.plist, which only the built app has.)
+  if (process.defaultApp) {
+    if (process.argv.length >= 2) app.setAsDefaultProtocolClient(SCHEME, process.execPath, [path.resolve(process.argv[1])]);
+  } else {
+    app.setAsDefaultProtocolClient(SCHEME);
+  }
+}
+
 function createWindow() {
   win = new BrowserWindow({
     width: 1400, height: 950, minWidth: 760, minHeight: 560,
@@ -260,7 +304,9 @@ function createWindow() {
   win.webContents.on("will-navigate", (e, target) => {
     if (!url || new URL(target).origin !== new URL(url).origin) e.preventDefault();
   });
-  win.on("closed", () => { win = null; });
+  // A reload or a new page must ask for links again before it gets any.
+  win.webContents.on("did-start-loading", () => { linkPage = null; });
+  win.on("closed", () => { win = null; linkPage = null; });
   load();
 }
 
@@ -326,10 +372,18 @@ function buildMenu() {
 if (!app.requestSingleInstanceLock()) {
   app.quit();
 } else {
-  app.on("second-instance", () => {
+  // macOS delivers install links here, even before the app is ready.
+  app.on("open-url", (e, link) => { e.preventDefault(); openInstallLink(link); });
+  // Windows and Linux start a second instance with the link as an argument.
+  app.on("second-instance", (_e, argv) => {
     if (win) { if (win.isMinimized()) win.restore(); win.focus(); }
+    const link = linkFromArgv(argv);
+    if (link) openInstallLink(link);
   });
+  const firstLink = IS_MAC ? null : linkFromArgv(process.argv);
+  if (firstLink) openInstallLink(firstLink);
   app.whenReady().then(() => {
+    registerScheme();
     buildMenu();
     createWindow();
   });
diff --git a/app/package.json b/app/package.json
index 944d660..bd5701a 100644
--- a/app/package.json
+++ b/app/package.json
@@ -21,6 +21,14 @@
   "build": {
     "appId": "com.saphid.frame-control",
     "productName": "Frame Control",
+    "protocols": [
+      {
+        "name": "Frame Control install link",
+        "schemes": [
+          "frame-control"
+        ]
+      }
+    ],
     "directories": {
       "output": "dist",
       "buildResources": "build"
@@ -28,6 +36,7 @@
     "files": [
       "main.js",
       "preload.js",
+      "install-link.js",
       "package.json",
       "build/icon.png"
     ],
@@ -55,6 +64,14 @@
           "*.py"
         ]
       },
+      {
+        "from": "../frame/devkit-utils",
+        "to": "frame/devkit-utils",
+        "filter": [
+          "**/*",
+          "!**/__pycache__/**"
+        ]
+      },
       {
         "from": "../apk-catalog",
         "to": "apk-catalog",
diff --git a/app/preload.js b/app/preload.js
index b921279..f21551d 100644
--- a/app/preload.js
+++ b/app/preload.js
@@ -1,7 +1,17 @@
 // Lets the page read this computer's clipboard through Electron, so sending it
-// to the Frame needs no pbpaste, PowerShell, xclip or wl-clipboard.
-const { contextBridge, ipcRenderer } = require("electron");
+// to the Frame needs no pbpaste, PowerShell, xclip or wl-clipboard. Also tells
+// the page where a dropped file or folder lives, so a folder can be sideloaded
+// as a title without zipping it (the local server reads it from there).
+// It also receives frame-control://install links (docs/web-install.md): only
+// what the link asked for, never an install; the page asks the user first.
+const { contextBridge, ipcRenderer, webUtils } = require("electron");
 
 contextBridge.exposeInMainWorld("frameApp", {
   readClipboard: () => ipcRenderer.invoke("clipboard:read"),
+  pathForFile: (file) => { try { return webUtils.getPathForFile(file) || ""; } catch { return ""; } },
+  onInstallLink: (cb) => {
+    ipcRenderer.removeAllListeners("install-link");
+    ipcRenderer.on("install-link", (_e, req) => cb({ kind: req.kind, target: req.target }));
+    ipcRenderer.send("install-link:ready");
+  },
 });
diff --git a/docs/frame-control.md b/docs/frame-control.md
index 43f37a1..0dfb4ae 100644
--- a/docs/frame-control.md
+++ b/docs/frame-control.md
@@ -56,7 +56,10 @@ python3 ui/server.py         # anywhere: then open http://127.0.0.1:47810
   (0.85–1.3×) over ADB (`wm size`, `wm density`, `font_scale`). Reset puts all
   three back. Whether the settings survive the app relaunching is untested.
 - **Transfer**: drag and drop files to `~/Downloads`; `.apk` files install as
-  their own Android app. Send typed text, or your computer's clipboard, to the
+  their own Android app. A game's `.zip`, folder or `.exe` becomes a title in
+  the Steam library (Valve's Devkit Game path, with Proton or the Steam Linux
+  Runtime picked from the program's header), listed under **Sideloaded titles**
+  with Launch and Remove; see [sideloading.md](sideloading.md). Send typed text, or your computer's clipboard, to the
   Frame clipboard.
 - **Flatpaks**: install and remove them (quick picks: Moonlight, Firefox, VLC,
   Remmina).
@@ -69,7 +72,7 @@ python3 ui/server.py         # anywhere: then open http://127.0.0.1:47810
 
 `app/` is an Electron shell. It starts `ui/server.py` on a free loopback port
 and shows it in its own window; the server stops when you quit the app. The
-app bundles `ui/`, `scripts/`, `frame/android/` and the rated catalogue from
+app bundles `ui/`, `scripts/`, `frame/android/`, Valve's `frame/devkit-utils/` and the rated catalogue from
 `apk-catalog/`, plus a standalone Python
 ([python-build-standalone](https://github.com/astral-sh/python-build-standalone))
 and `adb` from Google's platform-tools, so there's nothing else to install. It
@@ -95,7 +98,7 @@ library capsules and green Play buttons.
 both capture modes (headset view while in use, and a blank frame in standby,
 which the UI labels), clipboard, volume, file push, and input validation.
 **Not yet exercised from the UI:** Launch, Flatpak install/remove, APK drop,
-and the power buttons. Each of these calls a command that was verified
+title sideloading (not yet run on a headset at all), and the power buttons. Each of these calls a command that was verified
 separately.
 
 ## Per-platform notes
diff --git a/docs/how-the-frame-works.md b/docs/how-the-frame-works.md
index 20fbd33..315a889 100644
--- a/docs/how-the-frame-works.md
+++ b/docs/how-the-frame-works.md
@@ -48,7 +48,10 @@ Lepton (Android 11, podman container "lepton-dev") ← its own panel, app 305600
 | **DeoVR (Steam app 837380, Windows/Unity) runs immersively** under Proton ARM64 + FEX: Unity's OpenVR XR plugin finds `OpenVR Headset(Steam Frame)` and the `frame_controller`, the GPU shows as Turnip Adreno 750, and AVPro Video decodes through `MF-MediaEngine-Hardware`. It played 7680×3840 and 8192×4096 H.265 VR180 SBS streams in dome/fisheye mode (`FirstFrameReady`). Unity's own `VideoPlayer` (used for grid thumbnails) fails with `0xc00d36bb`, so thumbnail previews stay blank. The first launch takes about 45 s (`ComputeShaders: InitAsync`). Log: `compatdata/837380/pfx/drive_c/users/steamuser/AppData/LocalLow/Deo VR/Deo VR/Player.log`. **Verified 2026-09-25**, BUILD_ID 20260922.6101926. | [vr-video.md](vr-video.md) |
 | **Wolvic (VR browser APK) runs in Lepton against SteamVR's OpenXR**, with limits. The stock Lynx build aborts (`Runtime doesn't support selected swapChain color format`: it wants `GL_RGBA8`), and the stock Quest build fails with `XR_ERROR_API_VERSION_UNSUPPORTED`. Patching `DeviceDelegateOpenXR::GetSwapChainCreateInfo` in the Lynx build's `libnative-lib.so` to `GL_SRGB8_ALPHA8` (0x8C43) and re-signing fixes start-up. The Gecko engine then segfaults in `libxul`. The Chromium-engine build (Lynx v1.3-chromium) browses fine as an immersive app. Its page reports `isSessionSupported("immersive-vr") == true`, and `requestSession` succeeds, running about 36 rAF/s, but the headset shows **black** for WebXR content, or Wolvic's loading spinner that never clears, until the session is ended. Video decodes on the software `OMX.google.h264.decoder`. Tapping the URL bar's selection menu crashes it (no clipboard service). Open URLs with `am start -a VIEW -n com.igalia.wolvic/.VRBrowserActivity -d <url>` over the instance's ADB. DevTools is at `localabstract:content_shell_devtools_remote`. **Verified 2026-09-25**, BUILD_ID 20260922.6101926. | Web VR video, [apks.md](apks.md) |
 | Tailscale runs without root as a userspace `tailscaled` user service (static arm64 build in `~/.local/share/tailscale`, lingering on). In userspace mode, inbound tailnet connections reach the Frame's **loopback**, so every port, including DevTools on 8080, is reachable from the tailnet. **Verified 2026-09-25.** | [tailscale.md](tailscale.md), `scripts/tailscale-on-frame.sh` |
+| **T3 Code desktop runs natively.** The stock release `T3-Code-0.0.42-arm64.AppImage` in `~/Applications/T3CodeDesktop/` starts with no extra setup: glibc 2.39, `libfuse.so.2`, GTK 3, NSS and libsecret are on the image. `panel-on-frame.sh --name t3code-desktop -- '~/Applications/T3CodeDesktop/T3-Code.AppImage'` gives it its own panel (`valve.steam.desktopgame.2000281357`, `--ozone-platform=x11`). Its bundled server listens on `127.0.0.1:3773` and shows up in onboarding as the `frame` computer, with `passwordStore: gnome-libsecret`. The image has no agent CLI and no `node`. Agents run through the LAN CLIProxyAPI (`llm-proxy.lan:8317`, which resolves on the Frame). Claude Code 2.1.283 comes from `claude.ai/install.sh`, and Codex 0.157.1 from the `codex-aarch64-unknown-linux-musl` release tarball, both into `~/.local/bin`. `with-cliproxy` and a mode-600 `~/.config/cliproxyapi/secrets.env` are copied from the Mac. The wrappers `claude-cliproxy` and `codex-cliproxy` (a `-c model_provider=cliproxy`, `wire_api="responses"`, `env_key="CLIPROXY_API_KEY"`) are set as `providers.claudeAgent.binaryPath` and `providers.codex.binaryPath` in `~/.t3/userdata/settings.json`, and T3 picked that up without a restart. Through the wrappers, `claude auth status` reports `loggedIn: true` (`oauth_token`), and both CLIs answered a prompt with `kimi-k3`. `gamescopectl screenshot` captured another layer (the Lepton T3 app) rather than this panel. `DISPLAY=:0 xwd -id <win>` piped to `ffmpeg` captures the window itself (1920×1080). **Verified 2026-09-26**, BUILD_ID 20260922.6101926. | Running T3 Code as a host on the Frame |
 | Power actions need `sudo`, which asks for the Developer Mode password over SSH. | Frame Control's power buttons |
+| **Boot / recovery menu.** Hold Power ~10 s until the LED goes off, then power on while holding the **AUX button on top of the Power button** (not the volume keys) until a text menu appears. Entries: `Current` (SteamOS-A/B + build), `Previous` (the other A/B slot), `Boot from USB`, `Repair Steam Installation`, `Erase User Data` (factory reset), `ADB mode`, `Battery Ship Mode`. It auto-boots `Current` after a ~15 s countdown. **Volume Up/Down (left side) move, AUX (right side) selects.** For a boot loop, Valve says pick `Previous` (keeps user data); then `Repair Steam Installation`; `Erase User Data` wipes `~` (SSH keys, Tailscale, Flatpaks, T3 setup). Last resort is a full re-image, two ways: (1) USB: write `steamframe-repair-latest.img.bz2` to an 8 GB+ USB-C stick (Balena Etcher on the Mac), pick `Boot from USB`, then use "Wipe Device & Install SteamOS" / "Repair SteamOS" (keeps games and personal content) from the recovery desktop; (2) cable/EDL: `steamframe-repair-qdl-latest.tar.gz`, run `flash.sh` (Linux) or `flash.cmd` (Windows), then with the Frame off for 10 s hold Power + Vol Up + Vol Down for 10 s and plug it in; it reflashes and reboots. Both images: `https://steamdeck-images.steamos.cloud/recovery/` (build 20260922.5153644, 0.3.0, ~4 GB each, no published checksums); local copies in `~/Downloads/steam-frame-recovery/`. Source: Valve's [SteamOS Recovery FAQ](https://help.steampowered.com/en/faqs/view/1B71-EDF2-EB6D-2BB3) and [Installation and Repair FAQ](https://help.steampowered.com/en/faqs/view/65B4-2AA3-5F37-4227), plus a menu photo in [EloiStree/HelloSteamFrame#9](https://github.com/EloiStree/HelloSteamFrame/issues/9). **Inferred** (Valve docs, 2026-09-26); not yet tried on our Frame. | Recovering from a boot loop |
+| **Boot loop cause: the SteamVR health check.** `steamvr.service` runs `/usr/share/deckard/steamvr-health-check`, which appends `frog:glasses:` to `$XDG_RUNTIME_DIR/steamvr-short-session-tracker` on every failed or <10 s SteamVR run. At 3 it runs `steam-health-check --repair-now`, which **deletes all of `~/.local/share/Steam` (games, login, Developer Mode) and `~/.steam`**, keeping only `registry.vdf`. At 4 it also tries `steamos-bootconf set-mode reboot-other` (fails as the user: `bootenv: Permission denied`). SteamVR normally fails 1–2 times per boot while it waits for the Steam client (`SteamAPI_InitEx failed … Steam is probably not running`, then `fatal stalled cross-thread pipe`). Once Steam has been wiped, it has to re-download a ~210 MB client on every boot, so SteamVR keeps failing, Steam keeps getting wiped and the Frame reboots, in a loop. Also, the Steam updater can deadlock at `Installing update...` (main process blocked writing to the `-child-update-ui` process, which is stuck in `drm_syncobj_array_wait_timeout`). Killing only the `-child-update-ui` process lets the install finish (`package/*.installed` appears). **Fix without sudo:** over USB-C ADB (`adb -s frame shell` works as `steamos` while the Frame is looping; SSH is refused once Developer Mode is lost), truncate both `/run/user/1000/steam{,vr}-short-session-tracker` files and `chmod 444` them (the health check then logs `Permission denied` and does nothing; this is tmpfs, so it resets on reboot). Unstick the updater if needed, let Steam finish installing, then hold Power 10 s and start the Frame normally. `systemctl reboot` over ADB needs interactive auth. After the fix, sign in to Steam and turn Developer Mode back on. **Verified 2026-09-26**, BUILD_ID 20260922.6101926, slot B (clean boot: 0 SteamVR failures, SSH and Tailscale back). | Diagnosing a boot loop |
 
 ## Debug recipes
 
diff --git a/docs/install.html b/docs/install.html
new file mode 100644
index 0000000..4948d26
--- /dev/null
+++ b/docs/install.html
@@ -0,0 +1,63 @@
+<!doctype html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<meta name="referrer" content="no-referrer">
+<title>Install with Frame Control</title>
+<!-- Landing page for install links (docs/web-install.md): install.html?manifest=URL
+     or ?url=URL opens frame-control://install?… and offers the download if the
+     app doesn't open. Static, no requests of its own. Not published yet. -->
+<style>
+  body { margin: 0; min-height: 100vh; display: grid; place-items: center; background: #0d1117; color: #e6edf3;
+         font: 15px/1.5 -apple-system, "Segoe UI", sans-serif; }
+  main { max-width: 520px; padding: 32px; }
+  h1 { font-size: 20px; margin: 0 0 8px; }
+  p { color: #8b98a8; }
+  code { color: #e6edf3; overflow-wrap: anywhere; }
+  a.btn { display: inline-block; margin: 8px 12px 0 0; padding: 9px 16px; border-radius: 3px; text-decoration: none;
+          background: #2d333b; color: #e6edf3; }
+  a.btn.go { background: #1a9fff; color: #fff; font-weight: 600; }
+  .err { color: #ff7b72; }
+  [hidden] { display: none !important; }
+</style>
+</head>
+<body>
+<main>
+  <h1>Install with Frame Control</h1>
+  <p id="what"></p>
+  <p id="bad" class="err" hidden>This link doesn't name an https:// manifest or file, so there's nothing to install.</p>
+  <div id="actions" hidden>
+    <a class="btn go" id="open">Open in Frame Control</a>
+    <a class="btn" href="https://github.com/saphid/steam-frame/releases/latest">Get Frame Control</a>
+  </div>
+  <p id="missing" hidden>Nothing happened? Frame Control isn't installed on this computer, or is older than the
+    version that handles install links. Get it, open it once, then use the link again.</p>
+</main>
+<script>
+(() => {
+  const q = new URLSearchParams(location.search);
+  const kind = q.has("manifest") ? "manifest" : q.has("url") ? "url" : null;
+  const target = kind && q.get(kind);
+  let ok = false;
+  try {
+    const u = new URL(target);
+    const local = ["localhost", "127.0.0.1"].includes(u.hostname);
+    ok = !u.username && !u.password && (u.protocol === "https:" || (u.protocol === "http:" && local));
+  } catch {}
+  if (!ok) { document.getElementById("bad").hidden = false; return; }
+  const link = `frame-control://install?${kind}=${encodeURIComponent(target)}`;
+  document.getElementById("what").textContent = `From ${new URL(target).hostname}. Frame Control shows what it will `
+    + "install and asks you before downloading anything.";
+  document.getElementById("open").href = link;
+  document.getElementById("actions").hidden = false;
+  // If the app opens, this page loses focus or is hidden; if not, say how to get it.
+  let left = false;
+  window.addEventListener("blur", () => { left = true; });
+  document.addEventListener("visibilitychange", () => { if (document.hidden) left = true; });
+  setTimeout(() => { if (!left) document.getElementById("missing").hidden = false; }, 2000);
+  location.href = link;
+})();
+</script>
+</body>
+</html>
diff --git a/docs/scripts.md b/docs/scripts.md
index a1a1e0f..464c5a6 100644
--- a/docs/scripts.md
+++ b/docs/scripts.md
@@ -36,9 +36,11 @@ ssh frame                          # passwordless from now on
 `connect.sh` does four things:
 
 - finds the headset (`frame.local`, then `frame`, or the IP/host you pass in)
-- creates a dedicated key (`~/.ssh/id_ed25519_frame`)
+- creates dedicated keys (`~/.ssh/id_ed25519_frame`, plus `~/.ssh/id_rsa_frame_devkit` for pairing)
 - adds a `Host frame` block to `~/.ssh/config`
-- runs `ssh-copy-id`, which asks for the Developer Mode password once
+- tries SteamOS devkit pairing (approve on the headset, no password; **inferred**,
+  see [SSH](ssh.md#password-free-pairing-steamos-devkit-service)), else runs
+  `ssh-copy-id`, which asks for the Developer Mode password once
 
 Run `./scripts/connect.sh --harden` later if you want to turn off SSH password
 logins.
diff --git a/docs/sideloading.md b/docs/sideloading.md
new file mode 100644
index 0000000..6ff60e4
--- /dev/null
+++ b/docs/sideloading.md
@@ -0,0 +1,171 @@
+# Sideloading Linux and Windows games
+
+A game you have as files (an itch.io download, your own build, a DRM-free
+release) can go into the Frame's Steam library without a Steam store page.
+Frame Control uses the same path as Valve's
+[SteamOS Devkit Client](https://gitlab.steamos.cloud/devkit/steamos-devkit):
+the title becomes a Steam **Devkit Game**, with a runtime (Proton or a Steam
+Linux Runtime) chosen from the program itself.
+
+For Android APKs, see [apks.md](apks.md) instead.
+
+**Status: nothing here has run on a headset yet.** Every device-side step is
+**inferred from Valve's steamos-devkit source** (release v0.20260925.1). The
+local steps (reading the zip, picking the program and runtime, building the
+request) are covered by `tests/test_frame_titles.py`.
+
+## Using it
+
+Drop a game's `.zip`, folder or `.exe` on **Send to Frame**. (Folders need the
+desktop app, which knows where a dropped folder lives; in a plain browser, zip
+it.) A dialog shows:
+
+- **Name**: what Steam shows. Steam uses the title id as the name, so it's
+  limited to letters, digits, `_` and `-`; the dialog shows the result.
+- **Launches**: the program picked to start the game, with the other
+  candidates in the list.
+- **Runtime**: picked from the program, see below. Windows programs can switch
+  between Proton Experimental and Proton (stable).
+
+Install copies it to the Frame and registers it with Steam; progress shows in
+the bar and the activity log. **Sideloaded titles** lists what's installed,
+with Launch and Remove. **Copy to ~/Downloads instead** keeps the old
+behaviour for a zip that isn't a game.
+
+From a terminal:
+
+```sh
+python3 ui/frame_titles.py inspect Game.zip          # what would be installed, no headset needed
+python3 ui/frame_titles.py install Game.zip [--name N] [--exe REL] [--runtime R]
+python3 ui/frame_titles.py list | launch ID | remove ID
+```
+
+## Choosing the runtime
+
+The program's header decides, not its file name:
+
+| Program | Runtime (Steam compat tool) | `steam_play` | Confidence |
+|---|---|---|---|
+| Windows `.exe`, x86-64 (PE machine `0x8664`) | `proton-experimental` | 1 | Inferred: ARM64 Proton runs x86-64 code through FEX |
+| Windows `.exe`, 32-bit x86 (`0x14c`) or ARM64 (`0xaa64`) | `proton-experimental` | 1 | Inferred |
+| Linux ELF, aarch64 (`e_machine` `0xB7`) | `SteamLinuxRuntime_4-arm64` | 0 | Verified: starts, but natively (see below) |
+| Linux ELF, x86-64 (`0x3E`) | `SteamLinuxRuntime_4` | 0 | Verified not to start: the runtime isn't installed (see below) |
+| Shell script | the runtime of the Linux binary beside it, else `SteamLinuxRuntime_4-arm64` | 0 | Guess |
+| Anything else (32-bit Linux, other CPUs, DLLs, data) | refused with a message | | |
+
+Proton Experimental is the default rather than stable because the Frame's
+ARM64 Proton and FEX stack is new and Proton fixes reach Experimental first.
+If a game misbehaves, reinstall it with Proton (stable).
+
+The aliases and settings are the ones Valve's client sends: `RUNTIME_ALIASES`
+in `devkit_client/__init__.py`, and `gui2._update_game`, which sets
+`steam_play=1, steam_play_debug=0, steam_play_debug_version=2019` for Proton
+and `steam_play=0` otherwise, plus `compat_tool=<alias>`. Valve's client only
+offers `SteamLinuxRuntime_4-arm64` and Lepton when the device reports itself
+as Deckard (the Frame).
+
+## Picking the program
+
+`ui/frame_titles.py` reads every file's header: ELF executables (PIE ones are
+told from shared libraries by their `PT_INTERP` segment), PE executables (not
+DLLs) and scripts with `#!`. A zip with a single top-level folder is treated
+as that folder. Candidates are ranked by:
+
+1. Not a helper: names like `UnityCrashHandler64`, `CrashReportClient`,
+   `*setup*`, `unins*`, `vc_redist*`, `dxsetup`, `*prereq*`, and anything under
+   `_CommonRedist`, `Redist`, `DirectX` or `Engine` go last.
+2. Platform: native ARM64 Linux, then Windows x86-64, then x86-64 Linux, then
+   other Windows builds.
+3. Name: a program named like the zip or folder (build words such as
+   `-linux-arm64` or `_v1.2` are dropped from the name).
+4. Depth, then size: Unreal's top-level `Game.exe` beats
+   `Game/Binaries/Win64/Game-Win64-Shipping.exe`.
+
+A top-level shell script beats a Linux binary one folder down (`run.sh` +
+`bin/game`); a binary next to a script wins. The list in the dialog lets you
+pick another.
+
+## What happens on the Frame (inferred)
+
+1. **Tools.** `frame/devkit-utils/` (Valve's scripts, vendored unmodified, MIT)
+   is copied to `~/devkit-utils`, where Valve's client puts it, unless the
+   stamp file there already matches. Files are merged, not replaced, so a
+   newer copy from Valve's client keeps its extra files.
+2. **Folder.** `python3 ~/devkit-utils/steamos-prepare-upload --gameid ID`
+   makes `~/devkit-game/ID` and prints `{user, directory}`.
+3. **Copy.** The files go there with `rsync -a --delete` on macOS and Linux,
+   or `scp -r` into a fresh folder that then replaces it on Windows. Then
+   `chmod -R 755`, the modes Valve's client gives an upload.
+4. **Register.** `python3 ~/devkit-utils/steam-client-create-shortcut --parms JSON`
+   with `{gameid, directory, argv: [target], env: {}, settings, clear_settings,
+   force_appid: "", lepton_args: ""}`. It writes `ID-argv.json`,
+   `ID-env.json` and `ID-settings.json` next to the folder, then sends
+   `create-shortcut` to the running Steam client over `~/.steam/steam.pipe`
+   (authenticated by `~/.steam/steam.token`) and waits up to 5 s for Steam's
+   answer file. Its `error`, for example "The Steam client is not running",
+   is shown as the install error. The files stay, so installing again with
+   Steam running finishes the job.
+5. **Launch** is `steam-devkit-rpc run-game gameid=ID`. **Remove** is
+   `steamos-delete --delete-title ID`, which deletes the folder and has Steam
+   drop shortcuts with no folder. Frame Control then removes the `ID-*.json`
+   files that Valve's script leaves behind.
+
+Frame Control also writes `~/devkit-game/ID-framecontrol.json` (name, source
+file, target, runtime, size). **Sideloaded titles** lists every folder in
+`~/devkit-game`, including titles uploaded with Valve's client.
+
+`argv` is one string, as in Valve's client (the start command may carry
+arguments), so a program path with spaces is sent in double quotes. How Steam
+splits that string is **not checked**.
+
+## Safety
+
+- Zips are unpacked on your computer first. Entries with absolute paths, `..`,
+  drive letters or `:` anywhere in the path, or links that point outside the
+  zip (or at a folder they're in) are refused. So are zips over 64 GB
+  unpacked, over 200,000 entries, more than 200× compressed past 1 GB, or
+  bigger than the free space.
+- No symlink is created while unpacking, so no write can be redirected
+  through one. A link to a file inside the zip (`libfoo.so.1 → libfoo.so.1.2`)
+  becomes a copy of that file, which also works on Windows. Links to folders,
+  loops and dangling links are left out.
+- A dropped folder that contains symlinks (or Windows junctions) is copied on your computer first,
+  with the same rule, because `scp -r` would follow a link out of the folder
+  and upload whatever it points at.
+- Installs run one at a time, and Remove is refused while one runs.
+- The title id is limited to `[A-Za-z0-9_-]`, at most 64 characters. Valve's
+  scripts pass it to a shell (`steamos-delete` runs `rm -r` on it). Valve's
+  reserved sideload names (`steam`, `steamvr`, and their `deckard` forms,
+  which would replace the Steam client itself) get `-game` added.
+- Nothing needs `sudo`; everything goes to your home folder on the Frame.
+- In the app, a dropped folder is read from its local path by the app's own
+  server, which only accepts requests from its own page (see
+  [frame-control.md](frame-control.md#how-it-works)).
+
+## Checked on a headset
+
+Tested 2026-09-26 on a Frame (BUILD_ID 20260922.6101926) with small static test
+programs and PuTTY's official 64-bit `putty.exe`, through both the command line
+and the app (inspect, install job, ▶, Remove, and install links):
+
+- [x] `create-shortcut` registers a title; it shows in the Steam library and in
+  **Sideloaded titles**, and Steam maps it to the chosen compat tool.
+- [x] `steam-devkit-rpc run-game` starts it (Steam logs `devkit run-game: started
+  devkit game "<id>"`), and Remove (`steamos-delete`) deletes the files, the
+  shortcut and the Proton prefix.
+- [x] A quoted path in the start command is fine: Steam runs
+  `proton waitforexitandrun "/home/steamos/devkit-game/<id>/<exe>"`.
+- [x] An x86-64 Windows `.exe` runs under **Proton 11 (stable)** through FEX
+  (ARM64EC) inside the Steam Linux Runtime 4.0 ARM64 container; PuTTY stayed up.
+  Proton Experimental wasn't installed at the time (it was downloading), so it's
+  untested. A Go-built x86-64 test program crashed in `libarm64ecfex.dll`
+  (a FEX limitation with that program, not the sideloading).
+- [ ] **An aarch64 build runs natively, not in `SteamLinuxRuntime_4-arm64`**:
+  Steam records the mapping (`CompatToolMapping`, `compat_log.txt`) but launches
+  the devkit title without the runtime's `_v2-entry-point` prefix. Fine for a
+  self-contained build; a build that needs the runtime's libraries may not start.
+- [ ] **An x86-64 Linux build doesn't start**: Steam logs `Tool 4183110 "Steam
+  Linux Runtime 4.0" is found for appID …, but is not installed`, and the Frame
+  doesn't install that x86-64 runtime for a devkit title (a `steam://install/4183110`
+  request did nothing).
+- [ ] Whether these titles open as flat panels or need anything VR-specific.
diff --git a/docs/ssh.md b/docs/ssh.md
index 0b25cce..93aac3b 100644
--- a/docs/ssh.md
+++ b/docs/ssh.md
@@ -33,7 +33,8 @@ unless your router's DNS registers DHCP client names.
 
 - **Verified on device (2026-09-25):** `avahi-daemon` is running on the Frame
   and `frame.local` resolves from the Mac over mDNS.
-- `scripts/connect.sh` tries `frame.local`, then `frame`. If neither works, it tells you to re-run it with the IP.
+- `scripts/connect.sh` tries `frame.local`, then `frame`, then an mDNS browse for
+  the devkit service (below). If none works, it tells you to re-run it with the IP.
   Once you have a working address, the `Host frame` alias means you just type
   `ssh frame`.
 - To check discovery yourself: `dns-sd -G v4 frame.local` (Ctrl-C to stop), or
@@ -55,10 +56,49 @@ Host frame
   HostName frame.local
   User steamos
   IdentityFile ~/.ssh/id_ed25519_frame
+  IdentityFile ~/.ssh/id_rsa_frame_devkit
   IdentitiesOnly yes
   ServerAliveInterval 30
 ```
 
+The script only asks for the password if the pairing below doesn't work.
+
+## Password-free pairing (SteamOS devkit service)
+
+From Valve's source ([steamos-devkit-service](https://gitlab.steamos.cloud/devkit/steamos-devkit-service),
+[steamos-devkit](https://gitlab.steamos.cloud/devkit/steamos-devkit) client). **Verified on a
+Frame 2026-09-26** (BUILD_ID 20260922.6101926): the service runs with Developer Mode
+on, `properties.json` answers with `"login": "steamos"`, the headset advertises
+`_steamos-devkit._tcp` as `frame`, and `/register` needs pairing mode (below). The
+approve prompt and key install are not verified yet. SteamOS's devkit service is
+what Valve's Devkit Client uses to pair. `scripts/connect.sh` and
+`ui/frame_connect.py` try it first:
+
+- The headset serves HTTP on port **32000** and advertises mDNS
+  `_steamos-devkit._tcp`. `GET /properties.json` gives the `login` user; the
+  script uses it as `User` (unless you set `FRAME_USER`, or it says `root`),
+  for the password fallback too, and keeps it on re-runs.
+- **Open Steam Settings → Developer → Pair new host in the headset first.**
+  Otherwise `/register` answers at once with `403` `"please put the Steam client
+  in pairing mode: Settings -> Developer -> Pair new host"` (verified). The
+  scripts say so and keep asking for 2 minutes while you open it.
+- `POST /register` with `ssh-rsa <key> <comment> 900b919520e4cf601998a71eec318fec`
+  (a fixed token from Valve's client) shows an approve prompt inside the
+  headset naming the comment (`frame-control@<your computer>`). It waits 30 s,
+  then installs the key for the device user and turns `sshd` on. The reply is
+  `200 Registered`, or `403` with `{"error": ...}` (declined, timed out, Steam
+  not running).
+- It only accepts **RSA** keys, hence the second key,
+  `~/.ssh/id_rsa_frame_devkit` (3072-bit).
+- A host counts as found if port 22 **or** 32000 answers. With no host given,
+  and `frame.local`/`frame` unreachable, it browses `_steamos-devkit._tcp` with
+  `dns-sd` (macOS) or `avahi-browse` (Linux) for a few seconds if installed.
+- Port 32000 closed, a timeout, or an error: the script says why and falls back
+  to copying the ed25519 key with the Developer Mode password, as before.
+
+Anyone on your network can send the request, so only approve a prompt you
+started. `curl http://<frame-ip>:32000/properties.json` shows whether the service is up.
+
 `~/.ssh/authorized_keys` lives under `/home`, which SteamOS keeps across OS
 updates (inferred from Deck; the Frame uses the same A/B image scheme).
 
diff --git a/docs/web-install.md b/docs/web-install.md
new file mode 100644
index 0000000..d77dfd7
--- /dev/null
+++ b/docs/web-install.md
@@ -0,0 +1,158 @@
+# Install links for websites
+
+A website can put an "Install with Frame Control" button next to its download.
+Clicking it opens Frame Control, which shows what the link wants to install and
+asks the user. Only after they click **Install** does it download the file and
+install it on the Frame.
+
+What's verified: the link parsing, URL rules, manifest parsing, download,
+size cap and sha256 check, by `tests/test_webinstall.py` and
+`tests/test_server.py` (no network: a stub server on 127.0.0.1). Installing on
+the headset is the same code as dropping a file on Frame Control: `.apk` files go
+to the APK installer ([apks.md](apks.md)), `.zip` and `.exe` files to the
+Linux/Windows title installer. A link hasn't been clicked through to a headset
+install yet.
+
+## The link
+
+```
+frame-control://install?manifest=<URL-encoded manifest URL>
+frame-control://install?url=<URL-encoded file URL>
+```
+
+Use `manifest` when you can: it carries the title's name and a sha256, which
+Frame Control checks before installing. `url` is for a file on its own; the
+dialog then names the title after the file.
+
+The manifest is FrameDrop's format, so one manifest serves both apps. The
+schema may be `framedrop.install/v1` or `frame-control.install/v1`:
+
+```json
+{
+  "schema": "framedrop.install/v1",
+  "name": "My Game",
+  "files": [
+    { "url": "https://cdn.example.com/mygame-arm64.apk", "sha256": "optional-but-better" }
+  ]
+}
+```
+
+| Field | |
+|---|---|
+| `schema` | Required, one of the two above |
+| `name` | Shown in the confirm dialog (at most 120 characters). Defaults to the file name. APKs are still named in the Steam library by their own label |
+| `files` | Exactly one entry for now; more is refused with a message |
+| `files[0].url` | Required. The file to install |
+| `files[0].sha256` | Optional, 64 hex digits. The download must match or nothing is installed |
+| `files[0].size` | Optional (Frame Control extension), bytes. Shown up front; the download must match |
+| `files[0].exe` | Optional (Frame Control extension), for a `.zip` title: the program inside it to run |
+
+What gets installed depends on the file name's extension:
+
+| File | Installed as |
+|---|---|
+| `.apk` | An Android app in its own Lepton instance with a Steam shortcut ([apks.md](apks.md)) |
+| `.zip`, `.exe` | A Linux or Windows title. Versions of Frame Control without the title installer say "Linux/Windows titles need a newer Frame Control" |
+| anything else | Refused |
+
+## Rules
+
+Frame Control refuses a link, and downloads nothing, unless:
+
+- Every URL (the manifest's, the file's and each redirect) is `https://`.
+  `http://` works only for `localhost` or `127.0.0.1`, for testing: only when
+  Frame Control runs with `FRAME_CONTROL_LOCAL_LINKS=1`, and only when the
+  link itself points there. It's off by default so a website's link can't make
+  the app fetch from services on your computer, and a public manifest can
+  never send it there.
+- No URL has a user name or password in it (`https://user:pw@…`).
+- No host is, or resolves to, a private, loopback, link-local, CGNAT
+  (100.64.0.0/10), multicast or otherwise non-public address. Every address
+  the name has must be public, it's checked again on every redirect (at most
+  5), and the download connects to the address that was checked.
+- The file URL ends in a file name with one of the extensions above
+  (`https://example.com/games/` is refused).
+- The manifest is JSON of at most 256 KB, and the file at most 4 GiB
+  (`MAX_MANIFEST` and `MAX_FILE` in `ui/frame_webinstall.py`).
+- The user confirms. The dialog shows the title's name, the site the link came
+  from (and the file's host if different), the file name and type, the size if
+  known, and whether a sha256 was given.
+
+A web page can't install anything itself: it can only open the link. Frame
+Control's local server refuses requests from web pages, so the only way in is
+the operating system handing the link to the app, then the user's click.
+
+## Button for your site
+
+Paste this where the download is, with your manifest's URL in `MANIFEST`:
+
+```html
+<a id="frame-control-install" href="#"
+   style="display:inline-block;padding:10px 18px;border-radius:4px;background:#1a9fff;color:#fff;
+          font:600 15px -apple-system,'Segoe UI',sans-serif;text-decoration:none">Install with Frame Control</a>
+<script>
+(() => {
+  const MANIFEST = "https://example.com/mygame/frame-control.json";
+  const GET_APP = "https://github.com/saphid/steam-frame/releases/latest";
+  const button = document.getElementById("frame-control-install");
+  button.href = "frame-control://install?manifest=" + encodeURIComponent(MANIFEST);
+  button.addEventListener("click", () => {
+    // If Frame Control opens, this page loses focus; if it doesn't, offer the download.
+    let left = false;
+    const away = () => { left = true; };
+    window.addEventListener("blur", away, { once: true });
+    setTimeout(() => {
+      window.removeEventListener("blur", away);
+      if (!left && confirm("Frame Control didn't open. Download it?")) location.href = GET_APP;
+    }, 2000);
+  });
+})();
+</script>
+```
+
+For a single file, use `"frame-control://install?url=" + encodeURIComponent(FILE_URL)`.
+
+`docs/install.html` is a landing page that does the same from a plain link:
+`install.html?manifest=<URL-encoded URL>` tries the app and shows a "Get Frame
+Control" link. It isn't published anywhere yet; host a copy to use it.
+
+## Testing locally
+
+Start Frame Control with `FRAME_CONTROL_LOCAL_LINKS=1` in its environment (for
+example `FRAME_CONTROL_LOCAL_LINKS=1 npm start` in `app/`), then serve the
+manifest and file from your own computer:
+
+```sh
+cd mygame && python3 -m http.server 8000
+open 'frame-control://install?manifest=http%3A%2F%2Flocalhost%3A8000%2Fmanifest.json'   # xdg-open on Linux, start "" on Windows
+```
+
+The manifest's file URL must then be `http://localhost:8000/…` or
+`http://127.0.0.1:8000/…` too.
+
+## How it works
+
+- `app/install-link.js` parses the link (only `frame-control://install` with
+  exactly one `manifest` or `url`); `app/main.js` registers the scheme
+  (`app.setAsDefaultProtocolClient`, and electron-builder's `protocols` for the
+  macOS Info.plist and the Linux `.desktop` file). macOS delivers links through
+  `open-url`, Windows and Linux as an argument to a second instance. Links
+  wait in the main process until the page has loaded and asked for them
+  (`frameApp.onInstallLink` in `app/preload.js`). `framedrop://` is left alone.
+- The page posts the link to `/api/webinstall/check`, which reads the manifest,
+  applies the rules, asks the file's size with a HEAD request and returns a
+  one-time id. Nothing is downloaded.
+- **Install** posts the id to `/api/webinstall/start`. The server downloads to
+  a temporary folder (progress at `/api/webinstall/job`, cancellable with
+  `/api/webinstall/cancel`), checks size and sha256, hands the file to
+  `frame_webinstall.dispatch()` and deletes the folder.
+- The app registers the scheme each time it starts, so the last Frame Control
+  started (e.g. a development checkout) handles the links.
+
+**Quitting during a stalled download.** On macOS and Linux, quitting stops a
+download at once (`shutdown()` on its socket wakes the blocked read). On
+Windows that doesn't wake a read in another thread, and closing the handle
+under a TLS read isn't safe, so a download that has stalled holds the quit for
+the 4-second grace period until the app stops the server; the partial file is
+removed on the next start. Downloads that are still moving stop at their next
+read either way.
diff --git a/frame/devkit-utils/LICENSE b/frame/devkit-utils/LICENSE
new file mode 100644
index 0000000..bd7a5ef
--- /dev/null
+++ b/frame/devkit-utils/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017-2022 Valve Software inc., Collabora Ltd
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/frame/devkit-utils/README.md b/frame/devkit-utils/README.md
new file mode 100644
index 0000000..f97cbbe
--- /dev/null
+++ b/frame/devkit-utils/README.md
@@ -0,0 +1,18 @@
+# Valve's devkit-utils (vendored)
+
+Unmodified copy of `client/devkit-utils/` from Valve's
+[SteamOS Devkit Client](https://gitlab.steamos.cloud/devkit/steamos-devkit),
+MIT licensed (see `LICENSE`; Valve's own notes are in `VALVE-README.md`).
+
+- Source: steamos-devkit, commit `6f0711a` ("Code drop."),
+  release **v0.20260925.1** (ChangeLog entry dated 2026-09-25).
+
+`ui/frame_titles.py` copies this folder to `~/devkit-utils` on the Frame (where
+Valve's own client puts it) and uses `steamos-prepare-upload`,
+`steam-client-create-shortcut`, `steam-devkit-rpc` and `steamos-delete` to
+register uploaded builds as Steam "Devkit Games". See `docs/sideloading.md`.
+
+To update: copy the folder from a newer checkout over this one, keep this
+README, and update the version line above. The stamp Frame Control compares
+on the headset is a hash of these files, so a changed copy is re-synced on the
+next use.
diff --git a/frame/devkit-utils/VALVE-README.md b/frame/devkit-utils/VALVE-README.md
new file mode 100644
index 0000000..585a691
--- /dev/null
+++ b/frame/devkit-utils/VALVE-README.md
@@ -0,0 +1,4 @@
+These scripts and supporting utility module are uploaded to the devkit by the devkit client:
+
+- steamos-* : scripts that operate (mostly) at SteamOS level for devkit functionality purposes
+- steam-client-* : scripts that relay commands to the local running Steam client
diff --git a/frame/devkit-utils/deckard-capture b/frame/devkit-utils/deckard-capture
new file mode 100755
index 0000000..6cae14f
--- /dev/null
+++ b/frame/devkit-utils/deckard-capture
@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import sys
+import os
+import time
+import subprocess
+import logging
+import argparse
+import json
+import datetime
+import io
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+def main():
+    parser = argparse.ArgumentParser(description='Capture screenshot and videos on Steam Frame device')
+    parser.add_argument('--filename', '-f',
+                       default='/tmp/screenshot.png',
+                       help='Output')
+    parser.add_argument('--timestamp', action='store_true',
+                       help='Add timestamp')
+    parser.add_argument('--json', action='store_true',
+                       help='Output result as JSON')
+
+    args = parser.parse_args()
+
+    output_buffer = io.StringIO()
+    try:
+        steamvr_path = subprocess.check_output(['steamvr', 'path'], stderr=subprocess.STDOUT, universal_newlines=True).strip()
+        cdd = os.path.join(steamvr_path, 'bin/linuxarm64')
+        run_vrcmd = os.path.join(cdd, 'vrcmd')
+        assert os.path.exists(run_vrcmd), "vrcmd not found"
+
+        # Enable recording
+        cmd = [run_vrcmd, '--mailboxcmd', 'vrcompositor_systemlayer', 'set_local_video_record?enabled=true']
+        output_buffer.write(f"Command: {' '.join(cmd)}\n")
+        result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
+        output_buffer.write(result.stdout)
+        if result.returncode != 0:
+            raise subprocess.CalledProcessError(result.returncode, cmd)
+
+        # Wait for the video device to produce frames.
+        # Note that even when disabled it outputs roughly 2 blank frames per second.
+        cmd = ['timeout', '1', 'ffmpeg', '-f', 'v4l2', '-i', '/dev/video99', '-frames:v', '4', '-f', 'null', '-', '-v', 'error']
+        output_buffer.write(f"Command: {' '.join(cmd)}\n")
+        retries = 2
+        while True:
+            result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
+            output_buffer.write(result.stdout)
+            if result.returncode == 0:
+                break
+            retries -= 1
+            if retries <= 0:
+                raise Exception("Failed to get video frames from /dev/video99. Is VR active? Is the v4l2 configuration correct?")
+
+        output_filename = args.filename
+        if args.timestamp:
+            timestamp = datetime.datetime.now().strftime("%Y-%m-%d-%H-%M-%S")
+            base, ext = os.path.splitext(output_filename)
+            output_filename = f"{base}-{timestamp}{ext}"
+
+        # Capture screenshot
+        cmd = ['ffmpeg', '-f', 'v4l2', '-i', '/dev/video99', '-frames:v', '1', '-q:v', '1', '-y', output_filename]
+        output_buffer.write(f"Command: {' '.join(cmd)}\n")
+        result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
+        output_buffer.write(result.stdout)
+        if result.returncode != 0:
+            raise subprocess.CalledProcessError(result.returncode, cmd)
+
+        # Disable recording
+        cmd = [run_vrcmd, '--mailboxcmd', 'vrcompositor_systemlayer', 'set_local_video_record?enabled=false']
+        output_buffer.write(f"Command: {' '.join(cmd)}\n")
+        result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
+        output_buffer.write(result.stdout)
+        if result.returncode != 0:
+            raise subprocess.CalledProcessError(result.returncode, cmd)
+
+    except Exception as e:
+        error_msg = str(e)
+        # Print collected output to stderr on error
+        print(output_buffer.getvalue(), file=sys.stderr)
+        logger.error(error_msg)
+
+        if args.json:
+            result = {
+                'success': False,
+                'error': error_msg
+            }
+            print(json.dumps(result))
+        else:
+            print(f"Error: {error_msg}", file=sys.stderr)
+
+        return 1
+
+    if args.json:
+        result = {
+            'success': True,
+            'output': output_filename
+        }
+        print(json.dumps(result))
+    else:
+        print(f"Screenshot saved to {output_filename}")
+
+if __name__ == '__main__':
+    sys.exit(main())
\ No newline at end of file
diff --git a/frame/devkit-utils/devkit_utils/__init__.py b/frame/devkit-utils/devkit_utils/__init__.py
new file mode 100644
index 0000000..f02d7d4
--- /dev/null
+++ b/frame/devkit-utils/devkit_utils/__init__.py
@@ -0,0 +1,300 @@
+#!/usr/bin/env python
+# encoding: utf-8
+"""Utility functions for the Steam client hook scripts"""
+
+import sys
+import os
+import traceback
+import tempfile
+import json
+import logging
+import fcntl
+import errno
+import contextlib
+import time
+import fcntl
+
+
+import logging as logging_module
+logger = logging_module.getLogger(__name__)
+
+
+@contextlib.contextmanager
+def wrap_outputs(stderr_prefix):
+    # capture stderr to file to support debugging
+    stderr_fd = sys.stderr.fileno()
+    tf = tempfile.NamedTemporaryFile(
+        mode='w+',
+        prefix=stderr_prefix,
+        delete=True)
+    if sys.version_info >= (3, 4):
+        # this API in the os module is only available for python3
+        # but it does not seem to work with subprocess anyway
+        os.set_inheritable(tf.file.fileno(), True)
+        assert os.get_inheritable(tf.file.fileno())
+    sys.stderr = tf.file
+
+    # we can only write out a json response to stdout,
+    # so redirect stdout to stderr,
+    # and keep a handle on the original stdout for the response
+    stdout_fd = os.dup(sys.stdout.fileno())
+    os.dup2(sys.stderr.fileno(), sys.stdout.fileno())
+
+    ctx = {}
+    try:
+        yield ctx
+    except:
+        logger.error(traceback.format_exc())
+    finally:
+        tf.flush()
+        tf.seek(0)
+        os.write(stderr_fd, tf.read().encode('utf-8'))
+        if 'ret' in ctx:
+            os.write(stdout_fd, json.dumps(ctx['ret']).encode('utf-8'))
+
+
+class SteamClientNotRunningException(Exception):
+    def __init__(self, error_message):
+        self.error_message = error_message
+
+    def __str__(self):
+        return self.error_message
+
+
+def validate_steam_client():
+    """Verify that the steam client is running, and permissions are adequate"""
+    pid_path = os.path.normpath(
+        os.path.realpath(
+            os.path.expanduser('~/.steam/steam.pid')))
+    if not os.path.exists(pid_path):
+        raise SteamClientNotRunningException('{0} does not exist'.format(pid_path))
+    try:
+        pid = int(open(pid_path, 'rt').read())
+    except Exception:
+        raise SteamClientNotRunningException('{0} is invalid'.format(pid_path))
+    try:
+        os.kill(pid, 0)
+    except OSError:
+        raise SteamClientNotRunningException('{0} does not refer to a valid process'.format(pid_path))
+    logger.info('Found steam client pid %s', pid)
+
+
+def execute_steam_client_command(cmd):
+    """Send a command to the steam client over the IPC pipe"""
+    pipe_path = os.path.normpath(
+        os.path.realpath(
+            os.path.expanduser('~/.steam/steam.pipe')))
+    try:
+        pipe = open(pipe_path, 'wb+', 0)
+    except IOError:
+        raise Exception('cannot open steam client pipe')
+    session_token = open(os.path.expanduser('~/.steam/steam.token')).read()
+    #pipe_cmd = 'steam://{0}'.format(cmd)
+    # ^ hack to execute a normal command over the IPC directly - sometimes useful
+    pipe_cmd = 'devkit-1 steam://devkit-1/{0}/{1}'.format(
+        session_token,
+        cmd
+    )
+    logger.debug('Sending command line:')
+    logger.debug(pipe_cmd)
+    pipe.write('{0}\n'.format(pipe_cmd).encode('utf-8'))
+    pipe.close()
+
+
+def save_argv(gameid, argv):
+    """Save command line and arguments if provided"""
+
+    if argv is None:
+        return
+
+    argvfile = os.path.join(os.getenv("HOME"), "devkit-game",
+                            gameid + "-argv.json")
+    try:
+        with open(argvfile, "w") as argvf:
+            fcntl.flock(argvf, fcntl.LOCK_EX)
+            json.dump(argv, argvf)
+            fcntl.flock(argvf, fcntl.LOCK_UN)
+    except IOError:
+        raise Exception(
+            "Unable to open argv file for writing: {0}".format(argvfile))
+
+
+def obtain_argv(gameid, argv):
+    """Obtain command line with arguments"""
+
+    # If present and not None or [], just return the local arguments
+    if argv:
+        return argv
+
+    # From here, expect arguments to have been saved previously
+    argvfile = os.path.join(os.getenv("HOME"), "devkit-game",
+                            gameid + "-argv.json")
+    try:
+        with open(argvfile, "r") as argvf:
+            fcntl.flock(argvf, fcntl.LOCK_EX)
+            argv = json.load(argvf)
+            fcntl.flock(argvf, fcntl.LOCK_UN)
+    except IOError:
+        raise Exception(
+            "Unable to open argv file for reading: {0}".format(argvfile))
+    return argv
+
+
+def save_env(gameid, env):
+    """Save environment variables if provided"""
+
+    if not env:
+        return
+
+    envfile = os.path.join(os.getenv("HOME"), "devkit-game",
+                            gameid + "-env.json")
+    try:
+        with open(envfile, "w") as envf:
+            fcntl.flock(envf, fcntl.LOCK_EX)
+            json.dump(env, envf)
+            fcntl.flock(envf, fcntl.LOCK_UN)
+    except IOError:
+        raise Exception(
+            "Unable to open env file for writing: {0}".format(envfile))
+
+
+def obtain_env(gameid):
+    """Obtain environment variables for a game, if any were saved"""
+
+    envfile = os.path.join(os.getenv("HOME"), "devkit-game",
+                            gameid + "-env.json")
+    try:
+        with open(envfile, "r") as envf:
+            fcntl.flock(envf, fcntl.LOCK_EX)
+            env = json.load(envf)
+            fcntl.flock(envf, fcntl.LOCK_UN)
+    except IOError:
+        return {}
+    return env
+
+
+def save_settings(gameid, data):
+    """Save settings"""
+    settingsfile = os.path.join(os.getenv("HOME"), "devkit-game",
+                                gameid + "-settings.json")
+    settings = dict()
+
+    if data.get('clear_settings', False):
+        settings = {}
+    else:
+        try:
+            with open(settingsfile, "r") as f:
+                fcntl.flock(f, fcntl.LOCK_EX)
+                settings = json.load(f)
+                fcntl.flock(f, fcntl.LOCK_UN)
+        except IOError as e:
+            if (e.errno != errno.ENOENT):
+                raise
+
+    # Merge settings from new json
+    if 'settings' in data:
+        settings.update(data['settings'])
+
+    try:
+        with open(settingsfile, "w") as f:
+            fcntl.flock(f, fcntl.LOCK_EX)
+            json.dump(settings, f)
+            fcntl.flock(f, fcntl.LOCK_UN)
+    except (IOError):
+        raise Exception(
+            "Unable to open settings file for writing: {0}".format(
+                settingsfile
+            ))
+
+    return settings
+
+
+def load_settings(gameid):
+    settingsfile = os.path.join(os.getenv("HOME"), "devkit-game", gameid + '-settings.json')
+
+    if not os.path.isfile(settingsfile):
+        return None
+
+    with open(settingsfile, "r") as f:
+        fcntl.flock(f, fcntl.LOCK_EX)
+        settings = json.load(f)
+        fcntl.flock(f, fcntl.LOCK_UN)
+
+    return settings
+
+
+class SteamResponse_Timeout(Exception):
+    pass
+
+
+class SteamResponse_Error(Exception):
+    def __init__(self, error_response):
+        self.error_response = error_response
+
+    def __str__(self):
+        return self.error_response
+
+
+@contextlib.contextmanager
+def wait_on_file_response(path, timeout=5):
+    """
+The pipe to the Steam Client is one way.
+Responses from the Steam Client are written to filesystem.
+Protocol is as follows:
+- Steam Client creates a 'path.lock' file
+- Steam Client writes either 'path' or 'path.error' to indicate a problem
+- Steam Client deletes 'path.lock'
+- Caller (us) can then read the response
+
+NOTE 1: this function is used as a context manager and will block until a response comes in or timeout.
+
+NOTE 2: the files are created by Steam when responding to a command. If the files already exist the response protocol will break.
+    """
+    lock_path = '{0}.lock'.format(path)
+    error_path = '{0}.error'.format(path)
+    max_count = timeout
+    while True:
+        time.sleep(1)
+        if os.path.exists(error_path) or os.path.exists(path) and not os.path.exists(lock_path):
+            if os.path.exists(error_path):
+                with open(error_path, 'r') as f:
+                    fcntl.flock(f, fcntl.LOCK_EX)
+                    error_response = f.read()
+                    fcntl.flock(f, fcntl.LOCK_UN)
+                    raise SteamResponse_Error(error_response)
+            with open(path, 'r') as f:
+                fcntl.flock(f, fcntl.LOCK_EX)
+                success_response = f.read()
+                yield success_response
+                fcntl.flock(f, fcntl.LOCK_UN)
+                return
+        max_count -= 1
+        if max_count > 0:
+            continue
+        raise SteamResponse_Timeout()
+
+
+# Setting up as a context manager so we never miss the deletion
+# Creating a temporary .lock file to guard the create operation
+@contextlib.contextmanager
+def create_pid(pid_path):
+    os.makedirs(os.path.dirname(pid_path), exist_ok=True)
+    lock_path = '{0}.lock'.format(pid_path)
+    try:
+        lock_file = os.open(lock_path, os.O_CREAT | os.O_EXCL)
+    except IOError as e:
+        logger.error('cannot create lock file %s for pid file %s', lock_path, pid_path)
+        logger.error('remove the lock file manually and run again if you are confident no other instance is active')
+        raise
+
+    pid_file = open(pid_path,'w')
+    pid_file.write(str(os.getpid()))
+    pid_file.flush()
+    os.close(lock_file)
+    os.unlink(lock_path)
+    try:
+        yield pid_file
+    finally:
+        pid_file.close()
+        # Assume that's atomic and all is well, no need for another .lock
+        os.unlink(pid_path)
diff --git a/frame/devkit-utils/devkit_utils/resolve.py b/frame/devkit-utils/devkit_utils/resolve.py
new file mode 100644
index 0000000..1329926
--- /dev/null
+++ b/frame/devkit-utils/devkit_utils/resolve.py
@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import logging
+from urllib.parse import quote_plus as urllib_quote_plus
+import json
+import tempfile
+
+from . import validate_steam_client
+from . import execute_steam_client_command
+from . import wait_on_file_response
+
+import logging as logging_module
+logger = logging_module.getLogger(__name__)
+
+
+def resolve_shortcuts():
+    # make sure there is a steam client online that we can talk to before doing anything
+    validate_steam_client()
+
+    # scan the devkit games
+    installed_gameids = set([])
+    devkit_game_path = os.path.expanduser('~/devkit-game')
+    if not os.path.exists(devkit_game_path):
+        logger.info('%r does not exist, creating', devkit_game_path)
+        os.mkdir(devkit_game_path)
+    entries = sorted(os.scandir(devkit_game_path), key=lambda entry: entry.name)
+    directories = [e for e in entries if e.is_dir()]
+    for d in directories:
+        gameid = d.name
+        file_names = [f.name for f in entries if f.is_file() and f.name.startswith(gameid)]
+        has_argv = '{0}-argv.json'.format(gameid) in file_names
+        has_settings = '{0}-settings.json'.format(gameid) in file_names
+        if (not has_argv and not has_settings):
+            logger.info('Subfolder %r in %r is not accompanied by devkit configuration files, ignoring', d.name, devkit_game_path)
+            continue
+        logger.info('Found installed Devkit Game: %r', gameid)
+        installed_gameids.add(gameid)
+
+    # ask the Steam Client which Devkit Games are registered
+    with tempfile.TemporaryDirectory(prefix='list-shortcuts') as tempdir:
+        response = os.path.join(tempdir, 'shortcuts.json')
+        cmd = 'list-shortcuts?response={}'.format(
+            urllib_quote_plus(os.path.join(response))
+        )
+        # send the request
+        execute_steam_client_command(cmd)
+        with wait_on_file_response(response) as response:
+            client_shortcuts = json.loads(response)
+    logger.debug(client_shortcuts)
+    assert client_shortcuts['version'] == 2
+    registered_gameids = set([])
+    logger.info('Steam Client has %d registered devkit game(s)', len(client_shortcuts['gameids']))
+    for gameid in client_shortcuts['gameids']:
+        logger.info('Found Devkit Game registered with Steam Client: %r', gameid)
+        registered_gameids.add(gameid)
+
+    # any registered game that is not found installed on disk needs to be removed
+    for remove_gameid in registered_gameids - installed_gameids:
+        with tempfile.TemporaryDirectory(prefix='delete-shortcut') as tempdir:
+            logger.info('Removing stale registered Devkit Game: %r', remove_gameid)
+            response = os.path.join(tempdir, 'shortcut-deleted')
+            cmd = 'delete-shortcut?response={}&gameid={}'.format(
+                urllib_quote_plus(response),
+                remove_gameid
+            )
+            execute_steam_client_command(cmd)
+            with wait_on_file_response(response) as response:
+                logger.info('from Steam Client: %s', response.strip())
+
+    # any installed game that is not found registered needs to be added
+    for add_gameid in installed_gameids - registered_gameids:
+        with tempfile.TemporaryDirectory(prefix='create-shortcut') as tempdir:
+            logger.info('Registering installed Dekit Game: %r', add_gameid)
+            response = os.path.join(tempdir, 'registered')
+            cmd = 'create-shortcut?response={}&gameid={}&directory={}'.format(
+                urllib_quote_plus(response),
+                add_gameid,
+                urllib_quote_plus(devkit_game_path)
+            )
+            execute_steam_client_command(cmd)
+            with wait_on_file_response(response) as response:
+                logger.info('from Steam Client: %s', response.strip())
+
+if __name__ == '__main__':
+    resolve_shortcuts()
diff --git a/frame/devkit-utils/steam-client-create-shortcut b/frame/devkit-utils/steam-client-create-shortcut
new file mode 100644
index 0000000..802edce
--- /dev/null
+++ b/frame/devkit-utils/steam-client-create-shortcut
@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+
+import os
+import logging
+import argparse
+import json
+import platform
+import tempfile
+from urllib.parse import quote_plus as urllib_quote_plus
+
+import devkit_utils
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger()
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    parser.add_argument('--parms', required=True, action='store')
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    parms = json.loads(conf.parms)
+    gameid = parms['gameid']
+    directory = parms['directory']
+    assert os.path.isdir(directory)
+
+    force_appid = parms['force_appid']
+    steam_appid_path = os.path.join(directory, 'steam_appid.txt')
+    if force_appid:
+        with open(steam_appid_path, 'w') as f:
+            f.write(force_appid + '\n')
+        logger.info(f'Wrote {steam_appid_path} with AppID {force_appid}')
+    elif os.path.exists(steam_appid_path):
+        # don't overwrite an existing steam_appid.txt file from the content tree
+        # NOTE: if the user sets an AppID through the tool, then delete it, we may leave it in place ..
+        # (that's ok for now, do a clean upload if you want to get rid of it)
+        logger.info(f'{steam_appid_path} already exists, leaving it in place')
+
+    # Lepton (Android runtime) titles: write UECommandLine.txt next to the .apk
+    is_lepton = parms['settings']['compat_tool'] == 'lepton'
+    uecommandline = parms['lepton_args'] if is_lepton else ''
+    uecommandline_path = os.path.join(directory, 'UECommandLine.txt')
+    if uecommandline:
+        with open(uecommandline_path, 'w') as f:
+            f.write(uecommandline + '\n')
+        logger.info(f'Wrote {uecommandline_path}')
+    elif os.path.exists(uecommandline_path):
+        # don't overwrite an existing UECommandLine.txt file from the content tree
+        # NOTE: if the user sets cmdline args through the tool, then clears them, we may leave it in place ..
+        # (that's ok for now, do a clean upload if you want to get rid of it)
+        logger.info(f'{uecommandline_path} already exists, leaving it in place')
+
+    logger.info(f'Updating command line and runtime settings for {gameid} on {platform.node()}')
+    devkit_utils.save_argv(gameid, parms['argv'])
+    devkit_utils.save_env(gameid, parms['env'])
+    devkit_utils.save_settings(gameid, parms)
+
+    ret = {}
+
+    try:
+        devkit_utils.validate_steam_client()
+    except devkit_utils.SteamClientNotRunningException as e:
+        skipping = 'The Steam client is not running. Registration did not complete.'
+        logger.warning(skipping)
+        ret['error'] = skipping
+    else:
+        with tempfile.TemporaryDirectory(prefix='create-shortcut') as tempdir:
+            logger.info(f'Registering Devkit Game {gameid} with Steam Client')
+            response = os.path.join(tempdir, 'registered')
+            cmd = 'create-shortcut?response={}&gameid={}'.format(
+                urllib_quote_plus(response),
+                gameid,
+            )
+            devkit_utils.execute_steam_client_command(cmd)
+            try:
+                with devkit_utils.wait_on_file_response(response) as success_response:
+                    logger.debug(success_response)
+                    ret['success'] = success_response
+            except devkit_utils.SteamResponse_Timeout:
+                ret['error'] = 'timeout - Steam client did not respond to registration request'
+            except devkit_utils.SteamResponse_Error as e:
+                ret['error'] = e.error_response
+
+    # response gets written out to stdout
+    print(json.dumps(ret))
diff --git a/frame/devkit-utils/steam-devkit-rpc b/frame/devkit-utils/steam-devkit-rpc
new file mode 100755
index 0000000..409542e
--- /dev/null
+++ b/frame/devkit-utils/steam-devkit-rpc
@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import logging
+import argparse
+import tempfile
+import urllib.parse
+import re
+
+import devkit_utils
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger()
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('command')
+    parser.add_argument('args', nargs='*')
+    conf = parser.parse_args()
+
+    try:
+        devkit_utils.validate_steam_client()
+    except devkit_utils.SteamClientNotRunningException as e:
+        logger.error(repr(e))
+        sys.exit(-1)
+    else:
+        with tempfile.TemporaryDirectory(prefix='steam-devkit-rpc') as tempdir:
+            response = os.path.join(tempdir, 'steam-devkit-rpc')
+            parms = {
+                'response' : response,
+            }
+            for arg in conf.args:
+                (k, v) = re.split('=', arg)
+                parms[k] = v
+            cmd = f'{conf.command}/?{urllib.parse.urlencode(parms)}'
+            devkit_utils.execute_steam_client_command(cmd)
+            try:
+                with devkit_utils.wait_on_file_response(response) as success_response:
+                    logger.info('success')
+                    sys.stdout.write(success_response)
+                    sys.exit(0)
+            except devkit_utils.SteamResponse_Timeout:
+                logger.error('timeout')
+            except devkit_utils.SteamResponse_Error as e:
+                logger.error('failed')
+                sys.stdout.write(e.error_response)
+                sys.exit(-1)
diff --git a/frame/devkit-utils/steamos-delete b/frame/devkit-utils/steamos-delete
new file mode 100644
index 0000000..c73a1bd
--- /dev/null
+++ b/frame/devkit-utils/steamos-delete
@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import shutil
+import logging
+import argparse
+import subprocess
+
+import devkit_utils.resolve
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+
+def session_select_command():
+    if shutil.which('holo-session-select'):
+        return 'holo-session-select'
+    return 'steamos-session-select'
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    parser.add_argument('--delete-title', required=False, action='store', help='Delete a devkit title by name')
+    parser.add_argument('--delete-all-titles', required=False, action='store_true', default=False, help='Delete all devkit titles uploaded')
+    parser.add_argument('--reset-steam-client', required=False, action='store_true', default=False, help='Reset Steam client and delete all local Steam content')
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    if conf.delete_all_titles:
+        subprocess.check_call('rm -rf ~/devkit-game/*', shell=True)
+    elif conf.delete_title:
+        gamepath = os.path.expanduser( os.path.join( '~/devkit-game', conf.delete_title ) )
+        if not os.path.isdir(gamepath):
+            print(f'Not found: {gamepath}')
+        else:
+            subprocess.check_call(f'rm -r {gamepath}', shell=True)
+
+    # synchronize the Steam client's view of the devkit games with the on disk state
+    try:
+        devkit_utils.resolve.resolve_shortcuts()
+    except Exception as e:
+        logger.warning(f'Steam client sync of devkit games failed: {e}')
+
+    if conf.reset_steam_client:
+        # first make sure any sideloaded trampoline has been deleted
+        devkit_steam_trampoline_path = os.path.join(DEVKIT_TOOL_FOLDER, 'devkit-steam')
+        if os.path.exists(devkit_steam_trampoline_path):
+            os.unlink(devkit_steam_trampoline_path)
+
+        # wipe the local Steam install
+        subprocess.check_call(f'rm -rf ~/.local/share/Steam', shell=True)
+
+        # restart the session, which will initiate a reinstall of Steam from the OS client
+        subprocess.check_call([session_select_command(), 'gamescope'])
diff --git a/frame/devkit-utils/steamos-dump-controller-config b/frame/devkit-utils/steamos-dump-controller-config
new file mode 100644
index 0000000..4195119
--- /dev/null
+++ b/frame/devkit-utils/steamos-dump-controller-config
@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+
+import os
+import logging
+import argparse
+import tempfile
+import json
+from urllib.parse import quote_plus as urllib_quote_plus
+
+import devkit_utils
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    parser.add_argument('--appid', required=False, action='store')
+    parser.add_argument('--gameid', required=False, action='store')
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    ret = {}
+
+    try:
+        devkit_utils.validate_steam_client()
+    except devkit_utils.SteamClientNotRunningException as e:
+        skipping = 'The Steam client is not running.'
+        logger.warning(skipping)
+        ret['error'] = skipping
+    else:
+        with tempfile.TemporaryDirectory(prefix='controller-config') as tempdir:
+            response = os.path.join(tempdir, 'dumpcontrollerconfig')
+            cmd = f'dumpcontrollerconfig?response={urllib_quote_plus(response)}'
+            if conf.appid:
+                cmd += f'&appid={conf.appid}'
+            if conf.gameid:
+                cmd += f'&gameid={conf.gameid}'
+            logger.debug(f'command: {cmd}')
+            devkit_utils.execute_steam_client_command(cmd)
+            try:
+                with devkit_utils.wait_on_file_response(response) as success_response:
+                    logger.debug(success_response)
+                    ret['success'] = success_response
+            except devkit_utils.SteamResponse_Timeout:
+                ret['error'] = 'timeout - Steam did not respond to the command request'
+            except devkit_utils.SteamResponse_Error as e:
+                ret['error'] = e.error_response
+
+    # response gets written out to stdout
+    print(json.dumps(ret))
diff --git a/frame/devkit-utils/steamos-get-status b/frame/devkit-utils/steamos-get-status
new file mode 100755
index 0000000..caaa010
--- /dev/null
+++ b/frame/devkit-utils/steamos-get-status
@@ -0,0 +1,443 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import re
+import shutil
+import subprocess
+import logging
+import enum
+import argparse
+import json
+import shlex
+import datetime
+import pathlib
+import socket
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+STEAM_EXTRA_ARGS_FILE = os.path.expanduser('~/.config/systemd/user/steam.service.d/extra_args.conf')
+
+WIRELESS_DISABLE_POWER_MANAGEMENT = '/usr/bin/steamos-polkit-helpers/steamos-disable-wireless-power-management'
+
+# Must match in gui2.py
+class SteamStatus(enum.Enum):
+    NOT_RUNNING = 0
+    ERROR = 1
+    OS = 2
+    OS_DEV = 3
+    SIDELOADED = 4
+
+    @classmethod
+    def from_string(cls, status_str):
+        if not status_str:
+            return cls.ERROR
+        try:
+            if '.' in status_str:
+                name = status_str.split('.')[-1]
+            else:
+                name = status_str
+            return cls[name]
+        except KeyError:
+            return cls.ERROR
+
+    @property
+    def description(self):
+        DESCRIPTIONS = {
+            SteamStatus.NOT_RUNNING: 'not running',
+            SteamStatus.OS: 'OS client',
+            SteamStatus.OS_DEV: 'OS client dev mode',
+            SteamStatus.SIDELOADED: 'sideloaded client',
+            SteamStatus.ERROR: 'error',
+        }
+        return DESCRIPTIONS[self]
+
+
+class SteamConfig(enum.Enum):
+    ERROR = 1
+    # Matching the SteamStatus numeric values
+    OS = 2
+    OS_DEV = 3
+    SIDELOADED = 4
+
+    @property
+    def description(self):
+        DESCRIPTIONS = {
+            SteamConfig.OS: 'OS client',
+            SteamConfig.OS_DEV: 'OS client dev mode',
+            SteamConfig.SIDELOADED: 'sideloaded client',
+            SteamConfig.ERROR: 'error',
+        }
+        return DESCRIPTIONS[self]
+
+
+SESSION_NAMES = ['gamescope', 'plasma-x11', 'plasma-x11-persistent', 'plasma-wayland', 'plasma-wayland-persistent']
+
+class SessionConfig(enum.IntEnum):
+    # note: matches SESSION_NAMES indexes
+    GAMESCOPE = 0
+    PLASMA_X11 = 1
+    PLASMA_X11_PERSISTENT = 2
+    PLASMA_WAYLAND = 3
+    PLASMA_WAYLAND_PERSISTENT = 4
+    ERROR = 5
+
+def cef_debugging():
+    '''Only sane way to check is to look for the listening port.'''
+    ret = subprocess.run('/usr/bin/ss -l -t -n -p | grep steamwebhelper | grep 8080 > /dev/null', shell=True)
+    return ( ret.returncode == 0 )
+
+def steam_process_get_path_and_args():
+    ret = subprocess.run(['pgrep', '-a', '-x', 'steam'], capture_output=True, text=True)
+    if ret.returncode != 0:
+        return None
+    # Proton may run a dummy 'steam' process that confused previous implementations of this logic
+    # look for a process who's real filename is 'steam'
+    for l in ret.stdout.splitlines():
+        try:
+            pid = int(l.split(' ')[0])
+        except:
+            continue
+        rp = os.path.realpath(f'/proc/{pid}/exe')
+        if os.path.basename(rp) == 'steam':
+            try:
+                with open(f'/proc/{pid}/cmdline', 'rb') as f:
+                    cmdline = f.read()
+                argv = [a.decode('utf-8', errors='replace') for a in cmdline.split(b'\x00') if a]
+                if len(argv) >= 2:
+                    path = argv[0]
+                    args = argv[1:]
+                    # strip -srt-logger-opened: injected by steam.sh at runtime
+                    args = [a for a in args if a != '-srt-logger-opened']
+                    return (path, args)
+                return (argv[0], [])
+            except Exception as e:
+                logger.warning(f'Failed to read /proc/{pid}/cmdline: {e}')
+                return None
+
+def steam_process_get_path():
+    try:
+        (path, _) = steam_process_get_path_and_args()
+    except:
+        return None
+    return path
+
+def steam_process_get_args():
+    try:
+        (_, args) = steam_process_get_path_and_args()
+    except:
+        return ''
+    return args
+
+def steam_status():
+    '''What is the status of the Steam client on the system?'''
+    s = steam_process_get_path()
+    if s is None:
+        return SteamStatus.NOT_RUNNING
+    if s.find('.local/share/Steam/') != -1:
+        if os.path.exists(os.path.expanduser('~/devkit-game/devkit-steam')):
+            return SteamStatus.OS_DEV
+        return SteamStatus.OS
+    if s.find('devkit-game/steam/') != -1 or s.find('devkit-game/steamdeckard/') != -1:
+        return SteamStatus.SIDELOADED
+    logger.warning(f'could not interpret pgrep result to determine steam client status: {s!r}')
+    return SteamStatus.ERROR
+
+def steam_configuration():
+    '''How is the Steam client configured to run?'''
+    devkit_steam_trampoline_path = os.path.join(DEVKIT_TOOL_FOLDER, 'devkit-steam')
+    if not os.path.exists(devkit_steam_trampoline_path):
+        return SteamConfig.OS
+    t = open(devkit_steam_trampoline_path, 'rt').read()
+    if t.find('SteamStatus.OS_DEV') != -1:
+        return SteamConfig.OS_DEV
+    if t.find('SteamStatus.SIDELOADED') != -1:
+        return SteamConfig.SIDELOADED
+    logger.warning(f'could not determine what {devkit_steam_trampoline_path} means to do')
+    return SteamConfig.ERROR
+
+
+def osclient_branch(is_deckard):
+    '''Which branch is the default Steam 'OS client' configured to use?'''
+    # makes more sense to return strings here
+    beta_path = os.path.expanduser('~/.steam/steam/package/beta')
+    if not os.path.exists(beta_path):
+        return 'default' # not sure that's valid actually - would be the desktop client, which will only run in desktop mode ..
+    t = open(beta_path, 'rt').readline().strip('\n')
+    try:
+        p = 'steamdeck_(.*)'
+        if re.match(p, t):
+            branch = re.split(p, t)[1]
+            return branch
+        # internal builds
+        p = 'steampal_(.*)_.*'
+        if re.match(p, t):
+            branch = re.split(p, t)[1]
+            return branch
+        if is_deckard:
+            p = 'linux_arm64_(.*)_.*'
+            if re.match(p, t):
+                branch = re.split(p, t)[1]
+                return branch
+        raise Exception('no match')
+    except:  # noqa: E722
+        logger.warning(f'could not determine the OS client branch config: {t!r}')
+    return 'error'
+
+def osclient_version(conf):
+    '''Which version is the Steam 'OS client'?'''
+    if conf.is_deckard:
+        # old Steam client was using linuxarm64/, which is now reserved for the SDK binaries
+        for folder in ('linuxarm64', 'steamrtarm64'):
+            fn = os.path.expanduser(f'~/.steam/steam/{folder}/builddate.txt')
+            if os.path.exists(fn):
+                return open(fn, 'rt').read()
+        return 'Unknown - no builddate.txt'
+    beta_path = os.path.expanduser('~/.steam/steam/package/beta')
+    if not os.path.exists(beta_path):
+        logger.warning(f'not found: {beta_path}')
+        return None
+    t = open(beta_path, 'rt').readline().strip('\n')
+    manifest = os.path.expanduser(f'~/.steam/steam/package/steam_client_{t}_ubuntu12.manifest')
+    if not os.path.exists(manifest):
+        logger.warning(f'not found: {manifest}')
+        return None
+    try:
+        version = int(re.search('"version".*"(.*)"', open(manifest,'rt').read()).group(1))
+        return version
+    except:
+        logger.warning(f'could not parse version out of {manifest}')
+        return None
+
+def session_config():
+    '''What is the graphics session configuration?'''
+    # RESTART_SESSION writes this file
+    conf_file = '/etc/sddm.conf.d/zz-steamos-autologin.conf'
+    if not os.path.exists(conf_file):
+        # fallback to the OS default
+        conf_file = '/etc/sddm.conf.d/steamos.conf'
+    if os.path.exists(conf_file):
+        s = open(conf_file, 'rt').read()
+        if s.find('plasmawayland.desktop') != -1:
+            return SessionConfig.PLASMA_WAYLAND_PERSISTENT
+        if s.find('plasma.desktop') != -1:
+            return SessionConfig.PLASMA_X11_PERSISTENT
+        if s.find('gamescope-wayland.desktop') != -1:
+            return SessionConfig.GAMESCOPE
+        if s.find('plasma-steamos-oneshot.desktop') != -1:
+            return SessionConfig.PLASMA_X11
+        if s.find('plasma-steamos-wayland-oneshot.desktop') != -1:
+            return SessionConfig.PLASMA_WAYLAND
+    else:
+        # if the conf file doesn't exist we are likely in the default config
+        # check for a running gamescope for sanity
+        if subprocess.call('pgrep -a -x gamescope', shell=True, stdout=subprocess.DEVNULL) == 0:
+            return SessionConfig.GAMESCOPE
+    # couldn't figure it out, halp
+    return SessionConfig.ERROR
+
+def session_select_command():
+    if shutil.which('holo-session-select'):
+        return 'holo-session-select'
+    return 'steamos-session-select'
+
+def get_os_info():
+    os_info = {}
+    try:
+        for k, v in [ s.split('=') for s in open('/etc/os-release').read().split('\n') if len(s) > 0 ]:
+            os_info[k] = v.strip('"')
+    except Exception as e:
+        logger.error(e)
+        logger.error('Failed to parse OS release file')
+    return os_info
+
+def steam_default_args(conf):
+    if conf.is_deckard:
+        # Frame currently uses a different setup
+        return []
+
+    try:
+        if os.path.exists('/usr/lib/steamos/steam-launcher'):
+            output = subprocess.check_output('cat /usr/lib/steamos/steam-launcher | grep ^steamargs=',
+                                             shell=True,
+                                             universal_newlines=True)
+            ret = [ v.strip('"') for v in re.findall('\".*?\"', output) ]
+            return ret
+    except:
+        logger.warning('Failed to obtain steam default arguments from /usr/lib/steamos/steam-launcher')
+
+    # Legacy SteamOS
+    try:
+        output = subprocess.check_output('cat /usr/bin/gamescope-session | grep ^steamargs',
+                                         shell=True,
+                                         universal_newlines=True)
+        ret = [ v.strip('"') for v in re.findall('\".*?\"', output) ]
+    except:
+        logger.warning('Failed to obtain steam default arguments from /usr/bin/gamescope-session')
+
+    # Hardcoded fallback
+    return  ['-steamos3', '-steampal', '-steamdeck', '-gamepadui']
+
+def frame_osclient_extra_args(conf, steam_status):
+    if not conf.is_deckard or steam_status != SteamStatus.OS:
+        return None
+    if os.path.exists(STEAM_EXTRA_ARGS_FILE):
+        try:
+            content = open(STEAM_EXTRA_ARGS_FILE, 'rt').read()
+            match = re.search(r'Environment="STEAM_EXTRA_ARGS=(.*)"', content)
+            if match:
+                return match.group(1).replace('\\"', '"')
+        except Exception as e:
+            logger.warning(f'Failed to parse steam extra args: {e}')
+    return None
+
+def user_password_is_set():
+    ret = subprocess.run('passwd', stdin=subprocess.DEVNULL, shell=True, capture_output=True, universal_newlines=True)
+    logger.debug(repr(ret))
+    return (ret.stderr.find('Current password:') != -1)
+
+def steam_launch_flags():
+    '''Pull various steam flags that affect title execution.'''
+    ret = {}
+    if not 'XDG_RUNTIME_DIR' in os.environ:
+        logger.warning('XDK_RUNTIME_DIR is not set')
+        return ret
+    env_folder = os.path.join(os.environ['XDG_RUNTIME_DIR'], 'steam/env')
+    if not os.path.isdir(env_folder):
+        return ret
+    for fn in os.listdir(env_folder):
+        filepath = os.path.join(env_folder, fn)
+        content = open(filepath, 'rt').read()
+        # Check if this is a declaration file with key=value pairs
+        if content.count('\n') > 1 or '=' in content:
+            # Parse key=value format with comments
+            for line in content.splitlines():
+                line = line.strip()
+                # Skip comments and empty lines
+                if not line or line.startswith('#'):
+                    continue
+                # Parse key=value pairs
+                if '=' in line:
+                    key, value = line.split('=', 1)
+                    ret[key.strip()] = value.strip()
+        else:
+            # Legacy format: filename is the key, file content is the value
+            ret[fn] = content.strip('\n')
+    return ret
+
+def renderdoc_replay_server_running():
+    ret = subprocess.run(['pgrep', '-x', 'renderdoccmd'], capture_output=True)
+    return ret.returncode == 0
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    parser.add_argument('--json', required=False, action='store_true')
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    os_info = get_os_info()
+    assert os_info is not None
+    conf.is_deckard = os_info.get('VARIANT_ID', None) == 'vr'
+    os_name = os_info.get('PRETTY_NAME', None)
+    os_version = os_info.get('BUILD_ID', None)
+
+    _steam_launch_flags = steam_launch_flags()
+
+    if not conf.is_deckard:
+        # this bit of cargo cult is Steam Deck only
+        try:
+            # disable wireless power management for devkit usage: less latency on commands
+            subprocess.check_call(WIRELESS_DISABLE_POWER_MANAGEMENT)
+        except subprocess.CalledProcessError as e:
+            logger.warning(e)
+
+    session_config = session_config()
+    # enum -> human readable
+    session_status = SESSION_NAMES[session_config] if session_config != SessionConfig.ERROR else 'error'
+
+    steam_status = steam_status()
+    cef_debugging_enabled = False
+    if steam_status != SteamStatus.NOT_RUNNING:
+        cef_debugging_enabled = cef_debugging()
+    steam_configuration = steam_configuration()
+    osclient_branch = osclient_branch(conf.is_deckard)
+    osclient_version = osclient_version(conf)
+
+    steam_status_description = steam_status.description
+    if steam_status in (SteamStatus.OS, SteamStatus.OS_DEV) :
+        steam_status_description += f', on branch {osclient_branch!r}'
+        if osclient_version is not None:
+            if conf.is_deckard:
+                # we get builddate.txt
+                steam_status_description += f', {osclient_version}'
+            else:
+                utc_date_string = datetime.datetime.fromtimestamp(osclient_version, datetime.UTC).isoformat()
+                steam_status_description += f', version {osclient_version} {utc_date_string}'
+
+    has_side_loaded_client = os.path.exists(
+        os.path.join(
+            DEVKIT_TOOL_FOLDER,
+            'steam'
+        )
+    )
+
+    _user_password_is_set = user_password_is_set()
+
+    _renderdoc_replay_server_running = renderdoc_replay_server_running()
+    _renderdoc_layer_enabled = _steam_launch_flags.get('ENABLE_VULKAN_RENDERDOC_CAPTURE', '0') == '1'
+
+    _hostname = socket.gethostname()
+
+    if conf.json:
+        ret = {
+            'is_deckard': conf.is_deckard,
+            'hostname': _hostname,
+            'os_name': os_name,
+            'os_version': os_version,
+            'os_info': os_info,
+            'session_status': session_status,
+            'session_options': SESSION_NAMES,
+            'session_select': session_select_command(),
+            'steam_status': str(steam_status),
+            'cef_debugging_enabled': cef_debugging_enabled,
+            'steam_status_description': steam_status_description,
+            'steam_configuration': str(steam_configuration),
+            'steam_osclient_branch': osclient_branch,
+            'steam_osclient_version': osclient_version,
+            'has_side_loaded_client': has_side_loaded_client,
+            'steam_default_args': steam_default_args(conf),
+            'steam_current_args': steam_process_get_args(),
+            'frame_osclient_extra_args': frame_osclient_extra_args(conf, steam_status),
+            'user_password_is_set': _user_password_is_set,
+            'steam_launch_flags': _steam_launch_flags,
+            'renderdoc_layer_enabled': _renderdoc_layer_enabled,
+            'renderdoc_replay_server_running': _renderdoc_replay_server_running,
+        }
+        json.dump(ret, sys.stdout, sort_keys=True, indent=4)
+    else:
+        logger.info(f'Hostname                 : {_hostname}')
+        logger.info(f'OS                       : {os_name}')
+        logger.info(f'OS version               : {os_version}')
+        logger.info(f'Session mode is          : {session_status}')
+        logger.info(f'Session select command   : {session_select_command()}')
+        logger.info(f'Steam client status      : {steam_status_description}')
+        logger.info(f'Steam client args        : {steam_process_get_args()!r}')
+        logger.info(f"Steam extra args (Frame) : {frame_osclient_extra_args(conf, steam_status)!r}")
+        logger.info(f"Steam CEF debug          : {'enabled' if cef_debugging_enabled else 'disabled'}")
+        logger.info(f'Steam client config      : {steam_configuration.description}')
+        logger.info(f'Steam OS client branch   : {osclient_branch}')
+        logger.info(f'Steam OS client version  : {osclient_version}')
+        logger.info(f"Sideloaded client        : {'available' if has_side_loaded_client else 'not installed'}")
+        logger.info(f'OS client arguments      : {steam_default_args(conf)!r}')
+        logger.info(f"User password is set     : {'yes' if _user_password_is_set else 'no'}")
+        logger.info(f"Steam launch flags       : {_steam_launch_flags}")
+        logger.info(f"RenderDoc layer enabled  : {'yes' if _renderdoc_layer_enabled else 'no'}")
+        logger.info(f"RenderDoc replay running : {'yes' if _renderdoc_replay_server_running else 'no'}")
diff --git a/frame/devkit-utils/steamos-list-games b/frame/devkit-utils/steamos-list-games
new file mode 100644
index 0000000..31cc305
--- /dev/null
+++ b/frame/devkit-utils/steamos-list-games
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+import os
+import logging
+import argparse
+import getpass
+import json
+from subprocess import DEVNULL
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    ret = []
+    if os.path.isdir(DEVKIT_TOOL_FOLDER):
+        for filename in os.listdir(DEVKIT_TOOL_FOLDER):
+            gamefolder = os.path.join(DEVKIT_TOOL_FOLDER, filename)
+            if os.path.isdir(gamefolder):
+                ret.append( {
+                    'gameid': filename,
+                } )
+
+    print(json.dumps(ret))
diff --git a/frame/devkit-utils/steamos-prepare-upload b/frame/devkit-utils/steamos-prepare-upload
new file mode 100644
index 0000000..8d59874
--- /dev/null
+++ b/frame/devkit-utils/steamos-prepare-upload
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import logging
+import argparse
+import getpass
+import json
+import shutil
+import subprocess
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    parser.add_argument('--gameid', required=True, action='store')
+    parser.add_argument('--restart-steam', required=False, default='0', action='store')
+    parser.add_argument('--use-mask-unmask', required=False, default='0', action='store')
+    parser.add_argument('--prevent-auto-repair', required=False, default='0', action='store')
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    directory = os.path.join(
+        os.path.expanduser(DEVKIT_TOOL_FOLDER),
+        conf.gameid
+    )
+    os.makedirs(directory, exist_ok=True)
+
+    INHIBIT_SENTINEL = os.path.expanduser('~/.config/inhibit-short-session-tracker')
+    if int(conf.prevent_auto_repair) == 1:
+        open(INHIBIT_SENTINEL, 'w').close()
+        logger.info(f'Created sentinel file: {INHIBIT_SENTINEL}')
+    elif os.path.exists(INHIBIT_SENTINEL):
+        os.remove(INHIBIT_SENTINEL)
+        logger.info(f'Removed sentinel file: {INHIBIT_SENTINEL}')
+
+
+    ret = {
+        'user': getpass.getuser(),
+        'directory': directory,
+    }
+    print(json.dumps(ret))
diff --git a/frame/devkit-utils/steamos-set-password.sh b/frame/devkit-utils/steamos-set-password.sh
new file mode 100644
index 0000000..26b4bc3
--- /dev/null
+++ b/frame/devkit-utils/steamos-set-password.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+# meant to be executed remotely/interactively for password prompts
+
+# there's some annoying trash at the top of the remote ssh screen
+clear
+passwd
+sleep 2
diff --git a/frame/devkit-utils/steamos-set-steam-client b/frame/devkit-utils/steamos-set-steam-client
new file mode 100644
index 0000000..7d463af
--- /dev/null
+++ b/frame/devkit-utils/steamos-set-steam-client
@@ -0,0 +1,157 @@
+#!/usr/bin/env python3
+
+import sys
+import os
+import logging
+import argparse
+import enum
+import subprocess
+import shutil
+import pathlib
+
+logging.basicConfig(format='%(message)s', level=logging.DEBUG)
+logger = logging.getLogger(__name__)
+
+DEVKIT_TOOL_FOLDER = os.path.expanduser('~/devkit-game')
+# NOTE: only relevant to Frame + OS client with extra arguments
+# sideloaded client on Frame supports full command line edit instead 
+STEAM_EXTRA_ARGS_FILE = os.path.expanduser('~/.config/systemd/user/steam.service.d/extra_args.conf')
+
+class SteamStatus(enum.Enum):
+    # Supported values from steamos-get-status
+    OS = 2
+    OS_DEV = 3
+    SIDELOADED = 4
+
+STATUS_STRINGS = [
+    ( SteamStatus.OS, 'SteamStatus.OS' ),
+    ( SteamStatus.OS_DEV, 'SteamStatus.OS_DEV' ),
+    ( SteamStatus.SIDELOADED, 'SteamStatus.SIDELOADED' ),
+]
+
+# gamescope-session passes the execution to this script if it exists rather than start steam itself
+DEVKIT_STEAM_TRAMPOLINE = os.path.expanduser('~/devkit-game/devkit-steam')
+
+# this script executes the sideloaded Steam client (part of the steamos-devkit-service package)
+SIDE_LOADED_STEAM_CLIENT = '/usr/share/steamos-devkit/bin/devkit-standalone.py'
+
+def write_trampoline(text):
+    with open(DEVKIT_STEAM_TRAMPOLINE, 'w') as devkit_steam:
+        devkit_steam.write(text)
+        devkit_steam.flush()
+    os.chmod(DEVKIT_STEAM_TRAMPOLINE, 0o770)
+    # trying really hard to avoid leaving a zero sized trampoline if the deck is about to hang on the session restart coming next
+    subprocess.run(['/usr/bin/sync', DEVKIT_TOOL_FOLDER])
+
+def get_os_info():
+    os_info = {}
+    try:
+        for k, v in [ s.split('=') for s in open('/etc/os-release').read().split('\n') if len(s) > 0 ]:
+            os_info[k] = v.strip('"')
+    except Exception as e:
+        logger.error(e)
+        logger.error('Failed to parse OS release file')
+    return os_info
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', required=False, action='store_true')
+    parser.add_argument('--client', action='store', required=True, choices=[ v[1] for v in STATUS_STRINGS ])
+    parser.add_argument('--args', action='store', required=False, help='steam client command line arguments')
+    parser.add_argument('--gameid', required=True, action='store')
+    parser.add_argument('--gdbserver', action='store_true', required=False)
+    conf = parser.parse_args()
+
+    if conf.verbose:
+        logger.setLevel(logging.DEBUG)
+    else:
+        logger.setLevel(logging.INFO)
+
+    target = [ v for v in STATUS_STRINGS if v[1] == conf.client ][0][0]
+    logging.info(f'Set steam client on device to {target}')
+
+    if os.path.exists(DEVKIT_STEAM_TRAMPOLINE):
+        os.unlink(DEVKIT_STEAM_TRAMPOLINE)
+
+    os_info = get_os_info()
+    assert os_info is not None
+    is_deckard = os_info.get('VARIANT_ID', None) == 'vr'
+
+    if target == SteamStatus.OS:
+        if is_deckard:
+            # conf.args is the extra arguments for the normal Steam 'OS client', update it now
+            if conf.args is None or conf.args == '':
+                logger.info('Clearning extra arguments for normal Steam client')
+                if os.path.exists(STEAM_EXTRA_ARGS_FILE):
+                    os.unlink(STEAM_EXTRA_ARGS_FILE)
+                    subprocess.run(['systemctl', '--user', 'daemon-reload'], check=True)
+            else:
+                logger.info(f'Setting extra arguments for normal Steam client: {conf.args}')
+                os.makedirs(os.path.dirname(STEAM_EXTRA_ARGS_FILE), exist_ok=True)
+                with open(STEAM_EXTRA_ARGS_FILE, 'wt') as extra_args_file:
+                    escaped_args = conf.args.replace('"', '\\"')
+                    extra_args_file.write(f'[Service]\nEnvironment="STEAM_EXTRA_ARGS={escaped_args}"')
+                subprocess.run(['systemctl', '--user', 'daemon-reload'], check=True)
+
+            # When disabling a sideloaded client, also delete the ~/.steam symlinks:
+            # They will be re-created by the OS client when starting,
+            # this prevents SteamVR trying to use the sideloaded binaries that are still there for the steam API.
+            # (this may happen because SteamVR starts before Steam starts and has a chance to set those symlinks correctly)
+            for path in pathlib.Path(os.path.expanduser('~/.steam')).glob('*'):
+                if path.is_symlink():
+                    try:
+                        lnk = path.resolve()
+                        if 'devkit-game' in str(lnk):
+                            path.unlink()
+                            print(f'Deleted: {path} -> {lnk}')
+                    except Exception as e:
+                        print(f'Error processing {path}: {e}')
+        logger.info('Devkit Steam client override is disabled - default OS client execution will resume.')
+        sys.exit(0)
+
+    os.makedirs(os.path.dirname(DEVKIT_STEAM_TRAMPOLINE), exist_ok=True)
+
+    # OS client
+    steam_client = '$HOME/.local/share/Steam/steam.sh'
+    if target == SteamStatus.SIDELOADED:
+        steam_client = '$HOME/devkit-game/steam/steam.sh'
+
+    if is_deckard:
+        # RUNSTEAM.sh checks for SIDELOADED_STEAMROOT="${HOME}/devkit-game/steam"
+        # this is consistent with sideload on Steam Deck, but we use a different name 'steamdeckard'
+        # will be addressed when reworking the sideload and debug strategy, for now just drop in a symlink
+        steam_symlink = os.path.expanduser('~/devkit-game/steam')
+        if os.path.lexists(steam_symlink):
+            if os.path.islink(steam_symlink):
+                os.unlink(steam_symlink)
+            else:
+                # this happens if an upload in Steam Deck mode was attempted against a Steam Frame for instance
+                # was an easy mistake to make before recent changes
+                logger.warning('warning: ~/devkit-game/steam exists but is not a symlink. Removing anyway.')
+                shutil.rmtree(steam_symlink)
+        os.symlink(
+            os.path.expanduser('~/devkit-game/steamdeckard'),
+            steam_symlink,
+        )
+
+    args = '"$@"'
+    if conf.args is not None:
+        args = conf.args
+
+    gdbserver = ''
+    if conf.gdbserver:
+        logger.info('Configuring for remote debugging via gdbserver')
+        gdbserver = 'export DEBUGGER="gdbserver 0.0.0.0:2345"'
+
+    write_trampoline('''#!/bin/bash
+# Generated by steamos-set-steam-client, do not edit!
+# configuration tag (do not delete): {}
+{}
+mkdir -p $HOME/.steam/steam/logs
+exec {} {}
+'''.format(
+    conf.client,
+    gdbserver,
+    steam_client,
+    args
+))
diff --git a/scripts/connect.sh b/scripts/connect.sh
index 9ce6cd4..00bcb41 100755
--- a/scripts/connect.sh
+++ b/scripts/connect.sh
@@ -1,8 +1,10 @@
 #!/usr/bin/env zsh
-# Mac-side: find the Steam Frame, create a key, add a `Host frame` alias to
-# ~/.ssh/config, copy the key, and optionally disable SSH password logins.
+# Mac-side: find the Steam Frame, create keys, add a `Host frame` alias to
+# ~/.ssh/config, get a key onto the headset, and optionally disable SSH password
+# logins. It first pairs through Valve's SteamOS devkit service (port 32000:
+# approve on the headset, no password), else copies the key with the password.
 #
-# Verified on a Frame 2026-09-25 (except --harden). Idempotent: safe to re-run.
+# Verified on a Frame 2026-09-25 (except --harden and devkit pairing). Idempotent.
 #
 # Usage:
 #   scripts/connect.sh [HOST_OR_IP]          # set up key + alias
@@ -11,93 +13,232 @@
 # Env: FRAME_USER (default steamos), FRAME_ALIAS (default frame).
 set -euo pipefail
 
+user_from_env=${+FRAME_USER}
 FRAME_USER=${FRAME_USER:-steamos}
 FRAME_ALIAS=${FRAME_ALIAS:-frame}
 KEY="$HOME/.ssh/id_ed25519_frame"
+# The devkit service only accepts ssh-rsa keys, so pairing uses a second key.
+DEVKIT_KEY="$HOME/.ssh/id_rsa_frame_devkit"
 CONFIG="$HOME/.ssh/config"
 BEGIN_MARK="# >>> steam-frame ($FRAME_ALIAS) >>>"
 END_MARK="# <<< steam-frame ($FRAME_ALIAS) <<<"
+DEVKIT_PORT=32000
+DEVKIT_SERVICE=_steamos-devkit._tcp
+MAGIC_PHRASE=900b919520e4cf601998a71eec318fec  # fixed token Valve's client appends
+NAME_RE='^[A-Za-z0-9][A-Za-z0-9._-]*$'
+HOST_RE='^[A-Za-z0-9][A-Za-z0-9.:%-]*$'
 
 harden=0
 host_arg=""
 for arg in "$@"; do
   case "$arg" in
     --harden) harden=1 ;;
-    -h|--help) sed -n '2,11p' "$0"; exit 0 ;;
+    -h|--help) sed -n '2,13p' "$0"; exit 0 ;;
     *) host_arg="$arg" ;;
   esac
 done
 
 port_open() {
   # nc resolves through the system resolver (including mDNS for .local).
-  nc -z -G 3 "$1" 22 >/dev/null 2>&1
+  nc -z -G 3 "$1" "$2" >/dev/null 2>&1
+}
+
+# sshd, or the devkit service, which turns sshd on once a pairing is approved.
+reachable() {
+  port_open "$1" 22 || port_open "$1" $DEVKIT_PORT
+}
+
+# What a command printed within $1 seconds; dns-sd never exits by itself.
+run_for() {
+  local secs=$1; shift
+  "$@" 2>/dev/null &
+  local pid=$!
+  sleep "$secs"
+  kill $pid 2>/dev/null || true
+  wait $pid 2>/dev/null || true
+}
+
+# Hosts advertising the devkit service over mDNS (dns-sd -B, then -L each).
+discover_devkit() {
+  local name target
+  run_for 3 dns-sd -B $DEVKIT_SERVICE local. \
+    | sed -n "s/.* Add .*${DEVKIT_SERVICE//./\\.}\\.[[:space:]]*//p" | awk '!seen[$0]++' | head -n 4 \
+    | while IFS= read -r name; do
+        target=$(run_for 2 dns-sd -L "$name" $DEVKIT_SERVICE local. \
+          | sed -n 's/.* can be reached at \([^ :]*\):[0-9].*/\1/p' | head -n 1)
+        [[ -n "$target" ]] && print -r -- "${target%.}"
+      done | awk '!seen[$0]++'
 }
 
 pick_host() {
   local candidates=()
   [[ -n "$host_arg" ]] && candidates+=("$host_arg")
-  candidates+=("$FRAME_ALIAS.local" "$FRAME_ALIAS")
+  [[ -z "$host_arg" ]] && candidates+=("$FRAME_ALIAS.local" "$FRAME_ALIAS")
   local h
   for h in "${candidates[@]}"; do
-    if port_open "$h"; then
+    if reachable "$h"; then
       print -r -- "$h"; return 0
     fi
-    print -u2 "  - $h: not resolvable or port 22 closed"
+    print -u2 "  - $h: not resolvable, or ports 22 and $DEVKIT_PORT closed"
+  done
+  [[ -n "$host_arg" ]] && return 1
+  print -u2 "  - asking mDNS for $DEVKIT_SERVICE"
+  for h in ${(f)"$(discover_devkit)"}; do
+    if [[ "$h" =~ $HOST_RE ]] && reachable "$h"; then
+      print -r -- "$h"; return 0
+    fi
+    print -u2 "  - $h: advertised, but not reachable"
   done
   return 1
 }
 
+make_key() {  # path type comment [extra ssh-keygen args]
+  if [[ ! -f "$1" ]]; then
+    ssh-keygen -q -t "$2" "${@:4}" -N '' -C "$3" -f "$1"
+    print "    created $1"
+  else
+    print "    exists: $1"
+  fi
+}
+
+# Checks each step itself: pair_with_devkit calls this from an `elif`, where set -e is off.
+write_config() {
+  touch "$CONFIG" && chmod 600 "$CONFIG" || return 1
+  local tmp
+  tmp=$(mktemp) || return 1
+  # Drop any previous managed block, then PREPEND a fresh one: ssh uses the first
+  # value it sees per option, so this block must precede any other "Host frame"
+  # or "Host *". The trailing "Host *" returns the rest of the file to global scope.
+  awk -v b="$BEGIN_MARK" -v e="$END_MARK" '
+    $0==b {skip=1; next}
+    $0==e {skip=0; next}
+    !skip {print}
+  ' "$CONFIG" > "$tmp" || { rm -f "$tmp"; return 1; }
+  {
+    print -r -- "$BEGIN_MARK"
+    print -r -- "Host $FRAME_ALIAS"
+    print -r -- "  HostName $HOST"
+    print -r -- "  User $FRAME_USER"
+    print -r -- "  IdentityFile $KEY"
+    print -r -- "  IdentityFile $DEVKIT_KEY"
+    print -r -- "  IdentitiesOnly yes"
+    print -r -- "  ServerAliveInterval 30"
+    print -r -- "Host *"
+    print -r -- "$END_MARK"
+    cat "$tmp"
+  } > "$CONFIG" || { print -u2 "!! Writing $CONFIG failed; its previous contents are in $tmp"; return 1; }
+  rm -f "$tmp"
+}
+
+# accept-new: after pairing, this is the first contact, so trust a first-seen host
+# key (as ssh-copy-id's prompt would); a changed one still fails.
+key_login_works() {
+  ssh -o BatchMode=yes -o ConnectTimeout=5 -o StrictHostKeyChecking=accept-new "$FRAME_ALIAS" true 2>/dev/null
+}
+
+# The User in our managed block, so a re-run keeps one the headset named earlier.
+configured_user() {
+  [[ -f "$CONFIG" ]] || return 0
+  awk -v b="$BEGIN_MARK" -v e="$END_MARK" '
+    $0==b {inside=1; next}
+    $0==e {exit}
+    inside && $1=="User" {print $2; exit}
+  ' "$CONFIG"
+}
+
+devkit_url() {
+  if [[ "$HOST" == *:* ]]; then print -r -- "http://[$HOST]:$DEVKIT_PORT$1"
+  else print -r -- "http://$HOST:$DEVKIT_PORT$1"; fi
+}
+
+# Valve's steamos-devkit-service: GET /properties.json names the login user; POST
+# /register with "ssh-rsa <key> <comment> <magic>" shows an approve prompt in the
+# headset (the comment is what it displays, 30 s to answer), then installs the key
+# and turns sshd on. Returns non-zero with the reason in $devkit_why to fall back.
+devkit_why=""
+pair_with_devkit() {
+  local props login comment body resp code text err
+  print "==> Pairing through the headset's SteamOS devkit service (no password)"
+  if [[ ! -r "$DEVKIT_KEY.pub" ]]; then
+    devkit_why="can't read the pairing key $DEVKIT_KEY.pub"; return 1
+  fi
+  if ! props=$(curl -fsS --noproxy '*' -m 5 "$(devkit_url /properties.json)" 2>&1); then
+    devkit_why="devkit service not reachable on port $DEVKIT_PORT: ${${props##*curl: }%%$'\n'*}"; return 1
+  fi
+  # properties.json is Valve's json.dumps(indent=2): "login" sits on its own line.
+  login=$(print -r -- "$props" | sed -n 's/.*"login"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' | head -n 1)
+  [[ "$login" =~ $NAME_RE && "$login" != root ]] || login=""
+  # Before the prompt, so the password fallback uses this user too.
+  if [[ -n "$login" && "$login" != "$FRAME_USER" ]]; then
+    if (( user_from_env )); then
+      print "    the headset logs in as '$login'; keeping FRAME_USER=$FRAME_USER"
+    else
+      FRAME_USER=$login
+      print "    the headset logs in as '$FRAME_USER'"
+      write_config || { print -u2 "Could not rewrite $CONFIG."; exit 1; }
+    fi
+  fi
+  # One word: the headset splits the body on spaces and shows the third field.
+  comment="frame-control@$(hostname -s | tr -cs 'A-Za-z0-9._-' '-' | sed 's/^[-.]*//; s/[-.]*$//')"
+  [[ "$comment" == "frame-control@" ]] && comment="frame-control@computer"
+  body="ssh-rsa $(awk '{print $2}' "$DEVKIT_KEY.pub") $comment $MAGIC_PHRASE"
+  print "    In the headset: Steam Settings > Developer > Pair new host, then approve the request"
+  # The headset refuses at once unless Steam is on its "Pair new host" screen
+  # (verified on a Frame, 2026-09-26), so keep asking for 2 minutes while it's opened.
+  local deadline=$(( SECONDS + 120 ))
+  while true; do
+    if ! resp=$(print -r -- "$body" | curl -sS --noproxy '*' -m 60 -H 'Content-Type: text/plain' \
+        --data-binary @- -w '\n%{http_code}' "$(devkit_url /register)" 2>&1); then
+      devkit_why="devkit pairing failed: no answer (${${resp##*curl: }%%$'\n'*})"; return 1
+    fi
+    code=${resp##*$'\n'}
+    text=${resp%$'\n'*}
+    [[ "$code" == 2* ]] && break
+    err=$(print -r -- "$text" | sed -n 's/.*"error"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' | head -n 1)
+    devkit_why="devkit pairing failed: ${err:-${text:-HTTP $code}}"
+    [[ "$devkit_why" == *"pairing mode"* ]] && (( SECONDS < deadline )) || return 1
+    sleep 3
+  done
+  # The approval is what turns sshd on, so it may take a moment to answer.
+  local i
+  for i in {1..10}; do
+    key_login_works && return 0
+    sleep 1
+  done
+  devkit_why="paired, but key login still fails"; return 1
+}
+
 print "==> Looking for the Steam Frame"
 if ! HOST=$(pick_host); then
-  print -u2 "Could not reach the Frame on port 22."
+  print -u2 "Could not reach the Frame on port 22 or $DEVKIT_PORT."
   print -u2 "Check: Developer Mode on + user password set; same Wi-Fi; no client isolation."
   print -u2 "Then re-run with the IP from Quick Settings: scripts/connect.sh 192.168.x.y"
   exit 1
 fi
 print "    found: $HOST"
 
-print "==> SSH key"
+print "==> SSH keys"
 mkdir -p "$HOME/.ssh" && chmod 700 "$HOME/.ssh"
-if [[ ! -f "$KEY" ]]; then
-  ssh-keygen -q -t ed25519 -N '' -C "mac->steam-frame" -f "$KEY"
-  print "    created $KEY"
-else
-  print "    exists: $KEY"
-fi
+make_key "$KEY" ed25519 "mac->steam-frame"
+make_key "$DEVKIT_KEY" rsa "frame-control@$(hostname -s | tr -cs 'A-Za-z0-9._-' '-' | sed 's/^[-.]*//; s/[-.]*$//')" -b 3072
 
+if (( ! user_from_env )); then
+  prev_user=$(configured_user)
+  if [[ "$prev_user" =~ $NAME_RE ]]; then FRAME_USER=$prev_user; fi
+fi
 print "==> ~/.ssh/config alias '$FRAME_ALIAS' -> $HOST"
-touch "$CONFIG" && chmod 600 "$CONFIG"
-tmp=$(mktemp)
-# Drop any previous managed block, then PREPEND a fresh one: ssh uses the first
-# value it sees per option, so this block must precede any other "Host frame"
-# or "Host *". The trailing "Host *" returns the rest of the file to global scope.
-awk -v b="$BEGIN_MARK" -v e="$END_MARK" '
-  $0==b {skip=1; next}
-  $0==e {skip=0; next}
-  !skip {print}
-' "$CONFIG" > "$tmp"
-{
-  print -r -- "$BEGIN_MARK"
-  print -r -- "Host $FRAME_ALIAS"
-  print -r -- "  HostName $HOST"
-  print -r -- "  User $FRAME_USER"
-  print -r -- "  IdentityFile $KEY"
-  print -r -- "  IdentitiesOnly yes"
-  print -r -- "  ServerAliveInterval 30"
-  print -r -- "Host *"
-  print -r -- "$END_MARK"
-  cat "$tmp"
-} > "$CONFIG"
-rm -f "$tmp"
+write_config
 
 print "==> Checking key login"
-if ssh -o BatchMode=yes -o ConnectTimeout=5 "$FRAME_ALIAS" true 2>/dev/null; then
+if key_login_works; then
   print "    key login already works"
+elif pair_with_devkit; then
+  print "    paired; key login OK"
 else
+  print "    $devkit_why; falling back to the password"
   print "    copying key (enter the Developer Mode password once)"
   ssh-copy-id -i "$KEY.pub" -o IdentitiesOnly=yes "$FRAME_USER@$HOST"
-  ssh -o BatchMode=yes -o ConnectTimeout=5 "$FRAME_ALIAS" true \
-    || { print -u2 "Key login still failing after ssh-copy-id."; exit 1; }
+  key_login_works || { print -u2 "Key login still failing after ssh-copy-id."; exit 1; }
   print "    key login OK"
 fi
 
diff --git a/tests/test_connect.py b/tests/test_connect.py
new file mode 100644
index 0000000..b3366bd
--- /dev/null
+++ b/tests/test_connect.py
@@ -0,0 +1,218 @@
+"""Setup-script checks that need no headset: devkit pairing against a stub of Valve's
+steamos-devkit-service, the ~/.ssh/config block, and the mDNS output parsers.
+
+Run: python3 -m unittest discover -s tests
+"""
+import json
+import socket
+import sys
+import threading
+import unittest
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(ROOT / "ui"))
+
+import frame_connect as fc  # noqa: E402
+
+PUB = "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQC+/x= frame-control@old\n"
+
+
+class StubDevkit(BaseHTTPRequestHandler):
+    """Answers like steamos-devkit-service; `reply` picks the /register outcome."""
+    reply = (200, b"Registered\n")
+    replies = []  # if set, each /register takes the next one instead of `reply`
+    properties = {"txtvers": 1, "login": "steamos", "settings": "{}", "devkit1": ["devkit-1"]}
+    bodies = []
+
+    def log_message(self, *args):
+        pass
+
+    def do_GET(self):
+        if self.path == "/properties.json":
+            self.send_response(200)
+            self.send_header("Content-type", "application/json")
+            self.end_headers()
+            self.wfile.write(json.dumps(self.properties).encode())
+        else:
+            self.send_response(404)
+            self.end_headers()
+
+    def do_POST(self):
+        body = self.rfile.read(int(self.headers["Content-Length"]))
+        StubDevkit.bodies.append((self.path, self.headers["Content-Type"], body))
+        code, text = StubDevkit.replies.pop(0) if StubDevkit.replies else self.reply
+        self.send_response(code)
+        self.send_header("Content-type", "text/plain")
+        self.end_headers()
+        self.wfile.write(text)
+
+
+class DevkitPairing(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.server = ThreadingHTTPServer(("127.0.0.1", 0), StubDevkit)
+        cls.port = cls.server.server_address[1]
+        threading.Thread(target=cls.server.serve_forever, daemon=True).start()
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.server.shutdown()
+        cls.server.server_close()
+
+    def setUp(self):
+        StubDevkit.reply = (200, b"Registered\n")
+        StubDevkit.bodies = []
+        StubDevkit.replies = []
+        self.said = []
+        self._say, fc.say = fc.say, self.said.append
+
+    def tearDown(self):
+        fc.say = self._say
+
+    def test_register_body(self):
+        body = fc.register_body(PUB, "frame-control@mac")
+        self.assertEqual(body, "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQC+/x= frame-control@mac "
+                               "900b919520e4cf601998a71eec318fec\n")
+        # approve-ssh-key shows split(' ')[2] as the key name.
+        self.assertEqual(body.split(" ")[2], "frame-control@mac")
+        with self.assertRaises(ValueError):
+            fc.register_body("ssh-ed25519 AAAAC3Nz x", "c")
+
+    def test_key_comment_is_one_word(self):
+        self.assertEqual(fc.key_comment("Alex's MacBook Pro.local"), "frame-control@Alex-s-MacBook-Pro")
+        self.assertEqual(fc.key_comment(""), "frame-control@computer")
+        self.assertNotIn(" ", fc.key_comment(" a b\nc "))
+
+    def test_parse_login(self):
+        self.assertEqual(fc.parse_login(b'{"login": "steamos", "txtvers": 1}'), "steamos")
+        for raw in (b'{"txtvers": 1}', b'{"login": "root"}', b'{"login": "x\\nHost *"}', b'{"login": 5}'):
+            self.assertIsNone(fc.parse_login(raw), raw)
+        for raw in (b"not json", b"[1]"):
+            with self.assertRaises(ValueError):
+                fc.parse_login(raw)
+
+    def test_devkit_error(self):
+        self.assertEqual(fc.devkit_error(403, b'{"error": "Steam is not running"}\n'), "Steam is not running")
+        self.assertEqual(fc.devkit_error(500, b"install-ssh-key:\nboom"), "install-ssh-key:\nboom")
+        self.assertEqual(fc.devkit_error(403, b""), "HTTP 403")
+
+    def test_pair_ok(self):
+        logins = []
+        reason = fc.devkit_pair("127.0.0.1", PUB, "frame-control@test", self.port, logins.append)
+        self.assertIsNone(reason)
+        self.assertEqual(logins, ["steamos"])
+        path, ctype, body = StubDevkit.bodies[0]
+        self.assertEqual((path, ctype), ("/register", "text/plain"))
+        self.assertEqual(body.decode(), fc.register_body(PUB, "frame-control@test"))
+        self.assertTrue(any("Pair new host" in s for s in self.said))
+
+    NOT_PAIRING = (403, b'{"error": "devkit approve-ssh-key: please put the Steam client in pairing mode: '
+                        b'Settings -> Developer -> Pair new host"}')
+
+    def test_pair_waits_for_pairing_mode(self):
+        # The headset refuses until Steam is on "Pair new host", then prompts.
+        StubDevkit.replies = [self.NOT_PAIRING, self.NOT_PAIRING, (200, b"Registered\n")]
+        sleep, fc.time.sleep = fc.time.sleep, lambda s: None
+        try:
+            reason = fc.devkit_pair("127.0.0.1", PUB, "c", self.port)
+        finally:
+            fc.time.sleep = sleep
+        self.assertIsNone(reason)
+        self.assertEqual(len(StubDevkit.bodies), 3)
+
+    def test_pair_gives_up_without_pairing_mode(self):
+        StubDevkit.reply = self.NOT_PAIRING
+        wait, fc.PAIRING_MODE_WAIT = fc.PAIRING_MODE_WAIT, 0
+        try:
+            reason = fc.devkit_pair("127.0.0.1", PUB, "c", self.port)
+        finally:
+            fc.PAIRING_MODE_WAIT = wait
+        self.assertIn("pairing mode", reason)
+        self.assertEqual(len(StubDevkit.bodies), 1)
+
+    def test_pair_refused_falls_back(self):
+        StubDevkit.reply = (403, b'{"error": "timeout - Steam did not respond to the pairing request"}')
+        logins = []
+        reason = fc.devkit_pair("127.0.0.1", PUB, "c", self.port, logins.append)
+        self.assertIn("timeout - Steam did not respond", reason)
+        # The login is still reported, so the password fallback uses the right user.
+        self.assertEqual(logins, ["steamos"])
+
+    def test_pair_without_service_falls_back(self):
+        with socket.socket() as s:
+            s.bind(("127.0.0.1", 0))
+            closed = s.getsockname()[1]
+        logins = []
+        reason = fc.devkit_pair("127.0.0.1", PUB, "c", closed, logins.append)
+        self.assertIn("not reachable", reason)
+        self.assertEqual((logins, StubDevkit.bodies), ([], []))
+
+    def test_pair_times_out(self):
+        # Accepts the connection but never answers, like a prompt nobody taps.
+        with socket.socket() as s:
+            s.bind(("127.0.0.1", 0))
+            s.listen()
+            ok, msg = fc.register("127.0.0.1", "x", s.getsockname()[1], timeout=0.5)
+        self.assertFalse(ok)
+        self.assertIn("no answer", msg)
+
+
+class ConfigBlock(unittest.TestCase):
+    def test_both_keys(self):
+        block = fc.config_block("frame.local", 22, "steamos")
+        self.assertEqual(block[0], fc.BEGIN)
+        self.assertEqual(block[-1], fc.END)
+        self.assertIn("  User steamos", block)
+        self.assertNotIn("  Port 22", block)
+        files = [line for line in block if line.startswith("  IdentityFile")]
+        self.assertEqual(files, ["  IdentityFile ~/.ssh/id_ed25519_frame", "  IdentityFile ~/.ssh/id_rsa_frame_devkit"])
+        self.assertIn("  IdentitiesOnly yes", block)
+        self.assertEqual(block[-2], "Host *")
+        self.assertIn("  Port 2222", fc.config_block("10.0.0.5", 2222))
+
+    def test_write_config_replaces_block(self):
+        import tempfile
+        with tempfile.TemporaryDirectory() as d:
+            saved = fc.SSH_DIR, fc.CONFIG
+            fc.SSH_DIR, fc.CONFIG = Path(d), Path(d) / "config"
+            try:
+                fc.CONFIG.write_text("Host other\n  User me\n", encoding="utf-8")
+                fc.write_config("frame.local")
+                self.assertEqual(fc.configured_user(), "steamos")
+                fc.write_config("10.0.0.5", 22, "deck")
+                text = fc.CONFIG.read_text(encoding="utf-8")
+                self.assertEqual(fc.configured_user(), "deck")  # not "me" from Host other
+            finally:
+                fc.SSH_DIR, fc.CONFIG = saved
+        self.assertEqual(text.count(fc.BEGIN), 1)
+        self.assertIn("HostName 10.0.0.5", text)
+        self.assertIn("User deck", text)
+        self.assertNotIn("frame.local", text)
+        self.assertTrue(text.endswith("Host other\n  User me\n"))
+
+
+class MdnsParsers(unittest.TestCase):
+    def test_dns_sd(self):
+        browse = ("Browsing for _steamos-devkit._tcp\n"
+                  "Timestamp     A/R    Flags  if Domain               Service Type         Instance Name\n"
+                  "19:34:35.419  Add        3  15 local.               _steamos-devkit._tcp. frame\n"
+                  "19:34:35.611  Add        2   1 local.               _steamos-devkit._tcp. frame\n"
+                  "19:34:35.700  Add        2  15 local.               _steamos-devkit._tcp. My Frame\n"
+                  "19:34:36.000  Rmv        0  15 local.               _steamos-devkit._tcp. gone\n")
+        self.assertEqual(fc.parse_dns_sd_browse(browse), ["frame", "My Frame"])
+        resolve = ("Lookup frame._steamos-devkit._tcp.local.\n"
+                   "19:34:44.601  frame._steamos-devkit._tcp.local. can be reached at frame.local.:32000 (interface 15)\n")
+        self.assertEqual(fc.parse_dns_sd_resolve(resolve), "frame.local")
+        self.assertIsNone(fc.parse_dns_sd_resolve("Lookup frame\n"))
+
+    def test_avahi(self):
+        out = ('+;wlan0;IPv4;frame;_steamos-devkit._tcp;local\n'
+               '=;wlan0;IPv6;frame;_steamos-devkit._tcp;local;frame.local;fe80::1;32000;"login=steamos"\n'
+               '=;wlan0;IPv4;frame;_steamos-devkit._tcp;local;frame.local;192.168.1.50;32000;"login=steamos"\n')
+        self.assertEqual(fc.parse_avahi(out), ["frame.local", "192.168.1.50"])
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_frame_apk.py b/tests/test_frame_apk.py
index f9c008b..40119d4 100644
--- a/tests/test_frame_apk.py
+++ b/tests/test_frame_apk.py
@@ -4,6 +4,7 @@ import os
 import struct
 import sys
 import tempfile
+import tracemalloc
 import unittest
 import zipfile
 
@@ -134,6 +135,64 @@ class ApkInfo(unittest.TestCase):
             with self.assertRaises(frame_apk.ApkError):
                 self.read(data)
 
+    def test_refuses_oversized_members(self):
+        # An APK from a website mustn't make the server inflate gigabytes.
+        data = apk({'AndroidManifest.xml': manifest('com.example.big', 0x7f010000, 0x7f010001, 21)})
+        limit, frame_apk.MAX_MANIFEST = frame_apk.MAX_MANIFEST, 16
+        try:
+            with self.assertRaises(frame_apk.ApkError):
+                self.read(data)
+        finally:
+            frame_apk.MAX_MANIFEST = limit
+
+    def test_forged_sizes_dont_inflate_everything(self):
+        # The central directory claims 1 byte; the deflated data holds 16 MB of zeros.
+        buf = io.BytesIO()
+        with zipfile.ZipFile(buf, 'w', zipfile.ZIP_DEFLATED) as z:
+            z.writestr('AndroidManifest.xml', bytes(16 * 1024**2))
+        data = bytearray(buf.getvalue())
+        for sig, field in ((b'PK\x01\x02', 24), (b'PK\x03\x04', 22)):
+            at = data.index(sig)
+            data[at + field:at + field + 4] = struct.pack('<I', 1)
+        limit, frame_apk.MAX_MANIFEST = frame_apk.MAX_MANIFEST, 1024**2
+        tracemalloc.start()
+        try:
+            with self.assertRaises(frame_apk.ApkError):
+                self.read(bytes(data))
+            peak = tracemalloc.get_traced_memory()[1]
+        finally:
+            tracemalloc.stop()
+            frame_apk.MAX_MANIFEST = limit
+        self.assertLess(peak, 8 * 1024**2)
+
+    def test_refuses_compression_android_cant_read(self):
+        for method in (zipfile.ZIP_BZIP2, zipfile.ZIP_LZMA):
+            buf = io.BytesIO()
+            with zipfile.ZipFile(buf, 'w', method) as z:
+                z.writestr('AndroidManifest.xml', manifest('com.example.odd', 0x7f010000, 0x7f010001, 21))
+            with self.assertRaisesRegex(frame_apk.ApkError, 'compression'):
+                self.read(buf.getvalue())
+
+    def test_reference_cycles_and_fan_out_are_bounded(self):
+        res = frame_apk.Resources(b'')
+        ref = frame_apk.T_REF
+        res.entries = {1: [('', 0, ref, 1)] * 5}  # five references to itself
+        self.assertEqual(res.values(1), [])
+        # Five references at each of five hops: 3125 leaves without a budget.
+        res.entries = {i: [('', 0, ref, i + 1)] * 5 for i in range(1, 6)}
+        res.entries[6] = [('', 0, frame_apk.T_STRING, 0)]
+        self.assertEqual(len(res.values(1)), frame_apk.MAX_VALUES)
+        # Forty references at each hop round a four-id cycle: millions of dead ends.
+        looked = []
+
+        class Counting(dict):
+            def get(self, key, default=None):
+                looked.append(key)
+                return dict.get(self, key, default)
+        res.entries = Counting({i: [('', 0, ref, i % 4 + 1)] * 40 for i in range(1, 5)})
+        self.assertEqual(res.values(1), [])
+        self.assertLess(len(looked), frame_apk.MAX_STEPS + 10)
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/test_frame_titles.py b/tests/test_frame_titles.py
new file mode 100644
index 0000000..a46b508
--- /dev/null
+++ b/tests/test_frame_titles.py
@@ -0,0 +1,415 @@
+"""frame_titles without a headset: executable headers, launch targets, zips, runtimes."""
+import json
+import os
+import shutil
+import struct
+import sys
+import tempfile
+import unittest
+import zipfile
+
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'ui'))
+import frame_titles  # noqa: E402
+from frame_titles import FrameError  # noqa: E402
+
+
+def elf(machine, e_type=3, interp=True, pad=0):
+    """A 64-bit little-endian ELF header plus one program header (PT_INTERP or PT_LOAD)."""
+    ident = b'\x7fELF' + bytes([2, 1, 1]) + b'\0' * 9
+    header = ident + struct.pack('<HHIQQQIHHHHHH', e_type, machine, 1, 0, 64, 0, 0, 64, 56, 1, 0, 0, 0)
+    phdr = struct.pack('<IIQQQQQQ', 3 if interp else 1, 4, 0, 0, 0, 0, 0, 0)
+    return header + phdr + b'\0' * pad
+
+
+def pe(machine, dll=False, pad=0):
+    """An MZ stub pointing at a PE signature and COFF header."""
+    mz = b'MZ' + b'\0' * 0x3A + struct.pack('<I', 0x40)
+    coff = b'PE\0\0' + struct.pack('<HHIIIHH', machine, 1, 0, 0, 0, 0xF0, 0x2022 if dll else 0x0022)
+    return mz + coff + b'\0' * pad
+
+
+class Classify(unittest.TestCase):
+    def setUp(self):
+        self.dir = tempfile.mkdtemp()
+        self.addCleanup(shutil.rmtree, self.dir)
+
+    def check(self, data, name='f'):
+        p = os.path.join(self.dir, name)
+        with open(p, 'wb') as f:
+            f.write(data)
+        return frame_titles.classify(p)
+
+    def test_elf_machines(self):
+        self.assertEqual(self.check(elf(0xB7)), {'format': 'elf', 'arch': 'arm64', 'exe': True})
+        self.assertEqual(self.check(elf(0x3E))['arch'], 'x86_64')
+        self.assertEqual(self.check(elf(0x3E, e_type=2, interp=False))['exe'], True)   # ET_EXEC
+
+    def test_shared_library_is_not_a_program(self):
+        self.assertFalse(self.check(elf(0xB7, interp=False))['exe'])
+
+    def test_pe_machines(self):
+        self.assertEqual(self.check(pe(0x8664)), {'format': 'pe', 'arch': 'x86_64', 'exe': True})
+        self.assertEqual(self.check(pe(0xAA64))['arch'], 'arm64')
+        self.assertEqual(self.check(pe(0x14C))['arch'], 'x86')
+        self.assertFalse(self.check(pe(0x8664, dll=True))['exe'])
+
+    def test_lying_headers_are_not_programs(self):
+        bad = bytearray(elf(0xB7))
+        struct.pack_into('<HH', bad, 54, 1, 1)         # one-byte program header entries
+        self.assertFalse(self.check(bytes(bad))['exe'])
+        self.assertIsNone(self.check(b'MZ' + b'\0' * 0x3A + struct.pack('<I', 0xFFFFFFF0)))
+
+    def test_scripts_and_data(self):
+        self.assertEqual(self.check(b'#!/bin/sh\necho hi\n')['format'], 'script')
+        self.assertIsNone(self.check(b'MZ-not-really'))
+        self.assertIsNone(self.check(b'just text'))
+
+
+class Targets(unittest.TestCase):
+    def tree(self, files):
+        root = tempfile.mkdtemp()
+        self.addCleanup(shutil.rmtree, root)
+        for rel, data in files.items():
+            p = os.path.join(root, *rel.split('/'))
+            os.makedirs(os.path.dirname(p), exist_ok=True)
+            with open(p, 'wb') as f:
+                f.write(data)
+        return root
+
+    def plan(self, files, name):
+        return frame_titles.inspect(self.tree(files), name)
+
+    def test_unity_windows_build(self):
+        # UnityCrashHandler64.exe is bigger than the game's own exe; the name decides.
+        p = self.plan({'MyGame/MyGame.exe': pe(0x8664, pad=600),
+                       'MyGame/UnityCrashHandler64.exe': pe(0x8664, pad=5000),
+                       'MyGame/UnityPlayer.dll': pe(0x8664, dll=True, pad=9000),
+                       'MyGame/MyGame_Data/Plugins/x86_64/steam_api64.dll': pe(0x8664, dll=True)}, 'MyGame')
+        self.assertEqual(p['target'], 'MyGame.exe')
+        self.assertEqual(p['runtime'], 'proton-experimental')
+        self.assertEqual(p['runtimes'], ['proton-experimental', 'proton-stable'])
+        crash = next(c for c in p['candidates'] if c['path'] == 'UnityCrashHandler64.exe')
+        self.assertTrue(crash['skip'])
+        self.assertNotIn('UnityPlayer.dll', [c['path'] for c in p['candidates']])
+
+    def test_unreal_prefers_top_level_bootstrap(self):
+        p = self.plan({'Game.exe': pe(0x8664, pad=200),
+                       'Game/Binaries/Win64/Game-Win64-Shipping.exe': pe(0x8664, pad=9000),
+                       'Engine/Extras/Redist/en-us/UEPrereqSetup_x64.exe': pe(0x8664, pad=9000)}, 'Game')
+        self.assertEqual(p['target'], 'Game.exe')
+
+    def test_installers_lose_to_the_game(self):
+        p = self.plan({'setup.exe': pe(0x8664, pad=9000), 'unins000.exe': pe(0x14C, pad=9000),
+                       '_CommonRedist/vc_redist.x64.exe': pe(0x8664, pad=9000),
+                       'Tool.exe': pe(0x8664)}, 'Something')
+        self.assertEqual(p['target'], 'Tool.exe')
+
+    def test_arm64_linux_build(self):
+        p = self.plan({'game.arm64': elf(0xB7, pad=100), 'lib/libfoo.so': elf(0xB7, interp=False, pad=900)}, 'game')
+        self.assertEqual((p['target'], p['runtime']), ('game.arm64', 'SteamLinuxRuntime_4-arm64'))
+        self.assertEqual(p['runtimes'], ['SteamLinuxRuntime_4-arm64'])
+
+    def test_x86_64_linux_build_warns_it_may_not_start(self):
+        p = self.plan({'game.x86_64': elf(0x3E)}, 'game')
+        self.assertEqual(p['runtime'], 'SteamLinuxRuntime_4')
+        self.assertIn("won't start", p['note'])
+
+    def test_native_arm64_beats_x86_64(self):
+        p = self.plan({'game.x86_64': elf(0x3E, pad=900), 'game.arm64': elf(0xB7)}, 'game')
+        self.assertEqual(p['target'], 'game.arm64')
+
+    def test_top_level_script_beats_nested_binary(self):
+        p = self.plan({'run.sh': b'#!/bin/sh\nexec bin/game\n', 'bin/game': elf(0xB7)}, 'game')
+        self.assertEqual(p['target'], 'run.sh')
+        self.assertEqual(p['runtime'], 'SteamLinuxRuntime_4-arm64')
+
+    def test_binary_beside_script_wins(self):
+        p = self.plan({'start.sh': b'#!/bin/sh\n', 'game': elf(0x3E)}, 'game')
+        self.assertEqual(p['target'], 'game')
+
+    def test_other_architectures_are_refused(self):
+        with self.assertRaisesRegex(FrameError, 'x86 Linux'):
+            self.plan({'game': elf(0x03)}, 'game')
+        with self.assertRaisesRegex(FrameError, 'no Linux or Windows program'):
+            self.plan({'readme.txt': b'hello'}, 'game')
+
+    def test_runtime_override_and_exe_choice(self):
+        p = self.plan({'A.exe': pe(0x8664), 'B.exe': pe(0x8664)}, 'A')
+        frame_titles._choose(p, 'B.exe', 'proton-stable')
+        self.assertEqual((p['target'], p['runtime']), ('B.exe', 'proton-stable'))
+        with self.assertRaises(FrameError):
+            frame_titles._choose(p, 'A.exe', 'SteamLinuxRuntime_4-arm64')
+        with self.assertRaises(FrameError):
+            frame_titles._choose(p, '../outside.exe')
+
+    def test_exe_path_from_above_the_unwrapped_folder(self):
+        # A manifest names the program as it is in the archive: Game/B.exe, not B.exe.
+        p = self.plan({'Game/A.exe': pe(0x8664), 'Game/B.exe': pe(0x8664)}, 'Game')
+        self.assertEqual(p['unwrapped'], 'Game')
+        frame_titles._choose(p, 'Game/B.exe')
+        self.assertEqual(p['target'], 'B.exe')
+        frame_titles._choose(p, 'Game\\A.exe')
+        self.assertEqual(p['target'], 'A.exe')
+        with self.assertRaises(FrameError):
+            frame_titles._choose(p, 'Game/../../outside.exe')
+
+    def test_root_relative_path_wins_over_archive_prefix(self):
+        # Game/Game/A.exe and Game/A.exe: 'Game/A.exe' is a real path under the root Game/.
+        p = self.plan({'Game/Game/A.exe': pe(0x8664), 'Game/A.exe': pe(0x8664)}, 'Game')
+        self.assertEqual(p['unwrapped'], 'Game')
+        frame_titles._choose(p, 'Game/A.exe')
+        self.assertEqual(p['target'], 'Game/A.exe')
+
+    @unittest.skipIf(os.name == 'nt', 'needs symlinks')
+    def test_prefix_is_taken_before_staging(self):
+        # A folder with a link is staged into a temporary copy; the prefix still names
+        # the folders stepped into in the original.
+        d = self.tree({'Game/A.exe': pe(0x8664)})
+        os.symlink('A.exe', os.path.join(d, 'Game', 'link.exe'))
+        p = frame_titles.inspect(d, 'Game')
+        try:
+            self.assertEqual(p['unwrapped'], 'Game')
+            self.assertTrue(p['work'])
+        finally:
+            frame_titles.discard(p)
+
+
+class Zips(unittest.TestCase):
+    def setUp(self):
+        self.dir = tempfile.mkdtemp()
+        self.addCleanup(shutil.rmtree, self.dir)
+
+    def zip(self, members, name='Cool Game-v1.2-win64.zip'):
+        p = os.path.join(self.dir, name)
+        with zipfile.ZipFile(p, 'w') as z:
+            for n, data in members.items():
+                z.writestr(n, data)
+        return p
+
+    def test_wrapper_folder_and_name(self):
+        plan = frame_titles.inspect(self.zip({'Cool Game/Cool Game.exe': pe(0x8664),
+                                              '__MACOSX/Cool Game/._Cool Game.exe': b'x'}))
+        try:
+            self.assertEqual(plan['name'], 'Cool Game')
+            self.assertEqual(plan['id'], 'Cool_Game')
+            self.assertEqual(plan['target'], 'Cool Game.exe')
+            self.assertTrue(os.path.isfile(os.path.join(plan['root'], 'Cool Game.exe')))
+        finally:
+            frame_titles.discard(plan)
+        self.assertFalse(os.path.exists(plan['work']))
+
+    def test_zip_slip_is_refused(self):
+        for bad in ('../evil.exe', 'ok/../../evil.exe', '/abs/evil.exe', 'C:/evil.exe', '..\\evil.exe'):
+            with self.subTest(bad=bad):
+                out = tempfile.mkdtemp(dir=self.dir)
+                with self.assertRaisesRegex(FrameError, 'absolute|climbs'):
+                    frame_titles.extract_zip(self.zip({bad: pe(0x8664)}, 'bad.zip'), out)
+                self.assertFalse(os.path.exists(os.path.join(self.dir, 'evil.exe')))
+
+    def test_link_out_of_the_zip_is_refused(self):
+        p = os.path.join(self.dir, 'link.zip')
+        with zipfile.ZipFile(p, 'w') as z:
+            info = zipfile.ZipInfo('game/escape')
+            info.external_attr = (0o120777 << 16)
+            z.writestr(info, '../../etc/passwd')
+        with self.assertRaisesRegex(FrameError, 'outside'):
+            frame_titles.extract_zip(p, tempfile.mkdtemp(dir=self.dir))
+
+    def link_zip(self, members):
+        """members: (name, data, is_link) in order."""
+        p = os.path.join(self.dir, 'links.zip')
+        with zipfile.ZipFile(p, 'w') as z:
+            for name, data, is_link in members:
+                info = zipfile.ZipInfo(name)
+                info.external_attr = ((0o120777 if is_link else 0o100644) << 16)
+                z.writestr(info, data)
+        return p
+
+    def test_chained_links_cannot_escape(self):
+        # alias -> . ; alias/alias/escape -> ../.. ; escape/victim would land outside if links were real.
+        p = self.link_zip([('alias', '.', True), ('alias/alias/escape', '../..', True), ('escape/victim', b'x', False)])
+        out = tempfile.mkdtemp(dir=self.dir)
+        frame_titles.extract_zip(p, out)
+        self.assertTrue(os.path.isfile(os.path.join(out, 'escape', 'victim')))    # stayed inside
+        self.assertFalse(os.path.exists(os.path.join(self.dir, 'victim')))
+        self.assertFalse(os.path.exists(os.path.join(os.path.dirname(self.dir), 'victim')))
+        for root, dirs, files in os.walk(out):
+            self.assertFalse([n for n in dirs + files if os.path.islink(os.path.join(root, n))])
+
+    def test_folder_links_are_dropped_and_order_does_not_matter(self):
+        # b -> a/file listed before a -> dir; and a folder link that would contain itself.
+        p = self.link_zip([('dir/file', b'data', False), ('b', 'a/file', True), ('a', 'dir', True),
+                           ('dir/sub/loop', '../../a', True)])
+        out = tempfile.mkdtemp(dir=self.dir)
+        frame_titles.extract_zip(p, out)
+        with open(os.path.join(out, 'b'), 'rb') as f:
+            self.assertEqual(f.read(), b'data')
+        self.assertFalse(os.path.lexists(os.path.join(out, 'a')))
+        self.assertFalse(os.path.lexists(os.path.join(out, 'dir', 'sub', 'loop')))
+
+    def test_link_components_resolve_before_parent_steps(self):
+        # alias -> dirlink/../game.exe, dirlink -> deep/subdir: that's deep/game.exe, not game.exe.
+        p = self.link_zip([('deep/subdir/x', b'', False), ('deep/game.exe', b'deep one', False),
+                           ('game.exe', b'top one', False), ('dirlink', 'deep/subdir', True),
+                           ('alias', 'dirlink/../game.exe', True)])
+        out = tempfile.mkdtemp(dir=self.dir)
+        frame_titles.extract_zip(p, out)
+        with open(os.path.join(out, 'alias'), 'rb') as f:
+            self.assertEqual(f.read(), b'deep one')
+
+    def test_many_links_to_one_file_count_against_the_limit(self):
+        # The zip (1 KB) and the copies (15 KB) each fit under the limit; together they don't.
+        members = [('big', b'x' * 1000, False)] + [(f'alias{i}', 'big', True) for i in range(15)]
+        old = frame_titles.MAX_UNPACKED
+        frame_titles.MAX_UNPACKED = 15500
+        out = tempfile.mkdtemp(dir=self.dir)
+        try:
+            with self.assertRaisesRegex(FrameError, 'links would copy'):
+                frame_titles.extract_zip(self.link_zip(members), out)
+        finally:
+            frame_titles.MAX_UNPACKED = old
+        self.assertEqual(os.listdir(out), ['big'])   # refused before copying any link
+
+    def test_oversized_link_is_refused(self):
+        p = self.link_zip([('big', 'x' * 5000, True)])
+        with self.assertRaisesRegex(FrameError, 'oversized link'):
+            frame_titles.extract_zip(p, tempfile.mkdtemp(dir=self.dir))
+
+    @unittest.skipIf(os.name == 'nt', 'needs symlinks')
+    def test_unwrap_never_steps_through_a_link(self):
+        # A folder whose only entry links elsewhere (a junction on Windows) stays the boundary.
+        outside, game = os.path.join(self.dir, 'outside'), os.path.join(self.dir, 'Game')
+        os.makedirs(outside)
+        os.makedirs(game)
+        with open(os.path.join(outside, 'Other.exe'), 'wb') as f:
+            f.write(pe(0x8664))
+        os.symlink(outside, os.path.join(game, 'inner'))
+        with self.assertRaisesRegex(FrameError, 'no Linux or Windows program'):
+            frame_titles.inspect(game)
+
+    @unittest.skipIf(os.name == 'nt', 'needs symlinks')
+    def test_folder_with_outside_link_is_staged_without_it(self):
+        game, secret = os.path.join(self.dir, 'Game'), os.path.join(self.dir, 'secret')
+        os.makedirs(game)
+        os.makedirs(secret)
+        with open(os.path.join(secret, 'key'), 'wb') as f:
+            f.write(b'private')
+        with open(os.path.join(game, 'Game.exe'), 'wb') as f:
+            f.write(pe(0x8664))
+        os.symlink(secret, os.path.join(game, 'leak'))
+        os.symlink(os.path.join(secret, 'key'), os.path.join(game, 'leak-file'))
+        os.symlink('Game.exe', os.path.join(game, 'Alias.exe'))
+        plan = frame_titles.inspect(game)
+        try:
+            self.assertNotEqual(os.path.realpath(plan['root']), os.path.realpath(game))
+            self.assertEqual(sorted(os.listdir(plan['root'])), ['Alias.exe', 'Game.exe'])
+            self.assertFalse(os.path.islink(os.path.join(plan['root'], 'Alias.exe')))
+        finally:
+            frame_titles.discard(plan)
+
+    def test_links_become_copies(self):
+        # No symlinks on disk (Windows may not allow them); the library a link names is still there.
+        p = self.link_zip([('game/lib/libfoo.so.1.2', b'ELF-ish', False), ('game/lib/libfoo.so.1', 'libfoo.so.1.2', True),
+                           ('game/lib/libfoo.so', 'libfoo.so.1', True), ('game/dangling', 'nowhere', True)])
+        out = tempfile.mkdtemp(dir=self.dir)
+        frame_titles.extract_zip(p, out)
+        for name in ('libfoo.so.1', 'libfoo.so'):
+            path = os.path.join(out, 'game', 'lib', name)
+            self.assertFalse(os.path.islink(path))
+            with open(path, 'rb') as f:
+                self.assertEqual(f.read(), b'ELF-ish')
+        self.assertFalse(os.path.lexists(os.path.join(out, 'game', 'dangling')))
+
+    def test_drive_qualified_parts_are_refused(self):
+        for bad in ('sub/C:../C:../victim.txt', 'game/file.exe:stream'):
+            with self.subTest(bad=bad):
+                with self.assertRaisesRegex(FrameError, 'drive or stream'):
+                    frame_titles.extract_zip(self.zip({bad: b'x'}, 'drive.zip'), tempfile.mkdtemp(dir=self.dir))
+
+    def test_absurd_size_is_refused(self):
+        p = self.zip({'game.exe': pe(0x8664)}, 'bomb.zip')
+        old = frame_titles.MAX_UNPACKED
+        frame_titles.MAX_UNPACKED = 10
+        try:
+            with self.assertRaisesRegex(FrameError, 'looks wrong'):
+                frame_titles.extract_zip(p, tempfile.mkdtemp(dir=self.dir))
+        finally:
+            frame_titles.MAX_UNPACKED = old
+
+    def test_not_a_zip(self):
+        p = os.path.join(self.dir, 'x.zip')
+        with open(p, 'wb') as f:
+            f.write(b'nope')
+        with self.assertRaisesRegex(FrameError, 'not a readable zip'):
+            frame_titles.inspect(p)
+
+
+class Names(unittest.TestCase):
+    def test_title_id(self):
+        self.assertEqual(frame_titles.title_id('Hollow Knight: Silksong!'), 'Hollow_Knight_Silksong')
+        self.assertEqual(frame_titles.title_id('steam'), 'steam-game')     # Valve's reserved sideload names
+        self.assertEqual(frame_titles.title_id('Devkit Steam'), 'Devkit_Steam')
+        self.assertEqual(frame_titles.title_id('devkit-steam'), 'devkit-steam-game')  # the trampoline file
+        self.assertEqual(frame_titles.title_id('--rm -rf /'), 'rm_-rf')
+        self.assertEqual(len(frame_titles.title_id('x' * 200)), 64)
+        with self.assertRaises(FrameError):
+            frame_titles.title_id('!!!')
+
+    def test_display_name(self):
+        self.assertEqual(frame_titles.display_name('MyGame-linux-arm64.zip'), 'MyGame')
+        self.assertEqual(frame_titles.display_name('Portal 2.zip'), 'Portal 2')
+        self.assertEqual(frame_titles.display_name('Game_v1.0.3_Win64.zip'), 'Game')
+
+
+class Parms(unittest.TestCase):
+    def test_proton_parms(self):
+        p = frame_titles.shortcut_parms('Cool_Game', '/home/steamos/devkit-game/Cool_Game',
+                                        'Cool Game.exe', 'proton-experimental')
+        self.assertEqual(p, {'gameid': 'Cool_Game', 'directory': '/home/steamos/devkit-game/Cool_Game',
+                             'argv': ['"Cool Game.exe"'], 'env': {},
+                             'settings': {'steam_play': '1', 'steam_play_debug': '0',
+                                          'steam_play_debug_version': '2019',
+                                          'compat_tool': 'proton-experimental'},
+                             'clear_settings': True, 'force_appid': '', 'lepton_args': ''})
+        json.dumps(p)
+
+    def test_linux_parms(self):
+        p = frame_titles.shortcut_parms('g', '/home/steamos/devkit-game/g', 'bin/game', 'SteamLinuxRuntime_4-arm64')
+        self.assertEqual(p['argv'], ['bin/game'])
+        self.assertEqual(p['settings'], {'steam_play': '0', 'compat_tool': 'SteamLinuxRuntime_4-arm64'})
+
+    def test_cleanup_names_only_this_title(self):
+        # A glob like Game-*.json would also delete Game-Deluxe's files.
+        self.assertEqual(frame_titles._json_files('Game').split(),
+                         ['devkit-game/Game-argv.json', 'devkit-game/Game-env.json',
+                          'devkit-game/Game-settings.json', 'devkit-game/Game-framecontrol.json'])
+
+    def test_launch_needs_steam_to_answer(self):
+        # steam-devkit-rpc exits 0 after a timeout; only its 'success' line means Steam took it.
+        calls = []
+        old = frame_titles.ssh, frame_titles._check_id, frame_titles.ensure_utils
+        frame_titles._check_id, frame_titles.ensure_utils = (lambda g: g), (lambda: False)
+        try:
+            frame_titles.ssh = lambda cmd, **kw: calls.append(cmd) or 'Found steam client pid 1\ntimeout\n'
+            with self.assertRaisesRegex(FrameError, "didn't confirm"):
+                frame_titles.launch('Game')
+            frame_titles.ssh = lambda cmd, **kw: 'Found steam client pid 1\nsuccess\n{}'
+            self.assertEqual(frame_titles.launch('Game'), {'id': 'Game'})
+        finally:
+            frame_titles.ssh, frame_titles._check_id, frame_titles.ensure_utils = old
+        self.assertIn('steam-devkit-rpc run-game gameid=Game', calls[0])
+
+    def test_remove_waits_for_installs(self):
+        with frame_titles._install_lock:
+            with self.assertRaisesRegex(FrameError, 'install is running'):
+                frame_titles.remove('Game')
+
+    def test_vendored_utils_are_present(self):
+        for name in ('steamos-prepare-upload', 'steam-client-create-shortcut', 'steam-devkit-rpc',
+                     'steamos-delete', 'devkit_utils/__init__.py', 'LICENSE'):
+            self.assertTrue(os.path.isfile(os.path.join(frame_titles.UTILS_LOCAL, name)), name)
+        self.assertEqual(len(frame_titles.utils_stamp()), 20)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/tests/test_server.py b/tests/test_server.py
index 5511184..a1a7898 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -6,14 +6,17 @@ request guards and input validation, which all run before any SSH call.
 Run: python3 -m unittest discover -s tests
 """
 import http.client
+import io
 import json
 import os
 import socket
+import struct
 import subprocess
 import sys
 import tempfile
 import time
 import unittest
+import zipfile
 from pathlib import Path
 from urllib.parse import quote
 
@@ -54,7 +57,7 @@ class ServerGuards(unittest.TestCase):
     @classmethod
     def request(cls, method, path, body=None, headers=None):
         conn = http.client.HTTPConnection("127.0.0.1", cls.port, timeout=10)
-        data = json.dumps(body).encode() if body is not None else None
+        data = body if isinstance(body, bytes) else json.dumps(body).encode() if body is not None else None
         conn.request(method, path, body=data, headers=headers or {})
         r = conn.getresponse()
         payload = r.read()
@@ -130,6 +133,58 @@ class ServerGuards(unittest.TestCase):
         status, _ = self.post("/api/launch", ["not", "an", "object"])
         self.assertEqual(status, 400)
 
+    def test_title_upload_is_inspected_then_discarded(self):
+        # A zip holding a Windows x86-64 program: inspected locally, no SSH until install.
+        buf = io.BytesIO()
+        with zipfile.ZipFile(buf, "w") as z:
+            z.writestr("Tiny Game/Tiny Game.exe",
+                       b"MZ" + b"\0" * 0x3A + struct.pack("<I", 0x40) + b"PE\0\0" + struct.pack("<HHIIIHH", 0x8664, 1, 0, 0, 0, 0xF0, 0x22))
+        status, _, payload = self.request("POST", "/api/upload", buf.getvalue(),
+                                          {"X-Frame-UI": "1", "X-Mode": "title", "X-Filename": quote("Tiny Game-win64.zip")})
+        r = json.loads(payload)
+        self.assertEqual(status, 200, r)
+        self.assertEqual((r["plan"]["id"], r["plan"]["target"], r["plan"]["runtime"]),
+                         ("Tiny_Game", "Tiny Game.exe", "proton-experimental"))
+        self.assertNotIn("root", r["plan"])
+        self.assertEqual(self.post("/api/titles", {"action": "discard", "token": r["token"]})[0], 200)
+        self.assertEqual(self.post("/api/titles", {"action": "install", "token": r["token"]})[0], 400)
+
+    def test_title_input_validation(self):
+        status, _, _ = self.request("POST", "/api/upload", b"not a zip",
+                                    {"X-Frame-UI": "1", "X-Mode": "title", "X-Filename": "x.zip"})
+        self.assertEqual(status, 400)
+        for body in ({"action": "inspect", "path": "relative/game.zip"},
+                     {"action": "inspect", "path": "/nonexistent/frame-control/game.zip"},
+                     {"action": "install", "token": "nope"},
+                     {"action": "launch", "id": "x; rm -rf ~"},
+                     {"action": "remove", "id": "../etc"},
+                     {"action": "explode"}):
+            status, payload = self.post("/api/titles", body)
+            self.assertEqual(status, 400, f"{body} -> {payload}")
+        self.assertEqual(self.request("GET", "/api/titles/job?token=nope", headers={"X-Frame-UI": "1"})[0], 404)
+        self.assertEqual(self.request("POST", "/api/titles", {"action": "list"})[0], 403)
+
+    def test_web_install_needs_the_app_page(self):
+        # A website can only open frame-control:// links; it can't call these itself.
+        link = {"url": "https://cdn.example.com/game.apk"}
+        self.assertEqual(self.request("POST", "/api/webinstall/check", link)[0], 403)
+        self.assertEqual(self.request("POST", "/api/webinstall/start", {"id": "x"})[0], 403)
+        status, _, _ = self.request("POST", "/api/webinstall/check", link,
+                                    {"X-Frame-UI": "1", "Host": f"evil.example:{self.port}"})
+        self.assertEqual(status, 403)
+
+    def test_web_install_validation(self):
+        for body in ({}, {"url": 5}, {"url": "http://cdn.example.com/game.apk"}, {"url": "https://10.0.0.2/game.apk"},
+                     {"url": "https://u:p@example.com/game.apk"}, {"url": "https://example.com/"},
+                     {"url": "https://1.1.1.1/game.sh"}, {"manifest": "file:///etc/passwd"},
+                     {"manifest": "https://example.com/m.json", "url": "https://example.com/g.apk"}):
+            status, payload = self.post("/api/webinstall/check", body)
+            self.assertEqual(status, 400, f"{body} -> {payload}")
+        # Only an id from /check starts an install, and only once.
+        self.assertEqual(self.post("/api/webinstall/start", {"id": "made-up"})[0], 400)
+        self.assertEqual(self.request("GET", "/api/webinstall/job?id=x", headers={"X-Frame-UI": "1"})[0], 404)
+        self.assertEqual(self.post("/api/webinstall/cancel", {"job": "x"})[0], 404)
+
     def test_unknown_routes(self):
         self.assertEqual(self.request("GET", "/nope")[0], 404)
         self.assertEqual(self.post("/api/nope", {})[0], 404)
diff --git a/tests/test_webinstall.py b/tests/test_webinstall.py
new file mode 100644
index 0000000..1858297
--- /dev/null
+++ b/tests/test_webinstall.py
@@ -0,0 +1,438 @@
+"""Install links from websites (ui/frame_webinstall.py, app/install-link.js). No network:
+name lookups are stubbed and downloads come from a server on 127.0.0.1, which
+the localhost-testing rule allows.
+
+Run: python3 -m unittest discover -s tests
+"""
+import hashlib
+import json
+import os
+import shutil
+import socket
+import subprocess
+import sys
+import tempfile
+import threading
+import time
+import unittest
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from pathlib import Path
+from unittest import mock
+
+ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(ROOT / "ui"))
+
+import frame_webinstall as wi  # noqa: E402
+
+E = wi.WebInstallError
+PAYLOAD = b"not really an apk, but bytes are bytes\n" * 1000
+
+
+def fake_dns(*ips):
+    return lambda host, port, **_: [(socket.AF_INET, socket.SOCK_STREAM, 6, "", (ip, port)) for ip in ips]
+
+
+class Urls(unittest.TestCase):
+    def test_https_ok(self):
+        self.assertEqual(wi.check_url("https://cdn.example.com/g/mygame.apk"), ("https", "cdn.example.com", 443, False))
+        self.assertEqual(wi.file_name("https://cdn.example.com/g/my%20game.apk?sig=1"), "my game.apk")
+
+    def test_http_only_for_localhost(self):
+        with self.assertRaises(E):
+            wi.check_url("http://cdn.example.com/mygame.apk")
+        self.assertTrue(wi.check_url("http://localhost:8000/mygame.apk", allow_local=True)[3])
+        self.assertTrue(wi.check_url("http://127.0.0.1:8000/mygame.apk", allow_local=True)[3])
+
+    def test_localhost_only_when_the_link_starts_there(self):
+        for url in ("http://localhost/x.apk", "https://127.0.0.1/x.apk"):
+            with self.assertRaises(E):
+                wi.check_url(url, allow_local=False)
+
+    def test_other_schemes_rejected(self):
+        for url in ("file:///etc/passwd", "ftp://example.com/x.apk", "javascript:alert(1)", "//example.com/x.apk", ""):
+            with self.assertRaises(E, msg=url):
+                wi.check_url(url)
+
+    def test_private_and_local_addresses_rejected(self):
+        for host in ("10.0.0.5", "192.168.1.20", "172.16.3.4", "127.0.0.2", "169.254.169.254", "100.64.1.1",
+                     "0.0.0.0", "[::1]", "[fe80::1]", "[fd00::1]", "[fec0::1]", "[::ffff:192.168.1.1]",
+                     "[2002:c0a8:101::1]", "224.0.0.1"):
+            with self.assertRaises(E, msg=host):
+                wi.check_url(f"https://{host}/x.apk")
+        wi.check_url("https://93.184.216.34/x.apk")
+
+    def test_names_resolving_to_private_addresses_rejected(self):
+        with mock.patch.object(wi, "_getaddrinfo", fake_dns("192.168.1.9")):
+            with self.assertRaises(E):
+                wi._resolve("sneaky.example.com", 443, False)
+        # Every address counts, not just the first.
+        with mock.patch.object(wi, "_getaddrinfo", fake_dns("93.184.216.34", "10.1.2.3")):
+            with self.assertRaises(E):
+                wi._resolve("mixed.example.com", 443, False)
+        with mock.patch.object(wi, "_getaddrinfo", fake_dns("93.184.216.34")):
+            self.assertEqual(wi._resolve("cdn.example.com", 443, False), "93.184.216.34")
+
+    def test_credentials_rejected(self):
+        for url in ("https://user:pw@example.com/x.apk", "https://user@example.com/x.apk", "https://:pw@example.com/x.apk"):
+            with self.assertRaises(E, msg=url):
+                wi.check_url(url)
+
+    def test_directory_urls_rejected(self):
+        for url in ("https://example.com/", "https://example.com", "https://example.com/games/",
+                    "https://example.com/%2e%2e", "https://example.com/.hidden.apk", "https://example.com/a%2Fb.apk"):
+            with self.assertRaises(E, msg=url):
+                wi.file_name(url)
+
+    def test_file_types(self):
+        self.assertEqual(wi.file_kind("Game.APK"), "apk")
+        self.assertEqual(wi.file_kind("game.zip"), "title")
+        self.assertEqual(wi.file_kind("setup.exe"), "title")
+        for name in ("game.sh", "game.tar.gz", "game"):
+            with self.assertRaises(E, msg=name):
+                wi.file_kind(name)
+
+
+class Manifests(unittest.TestCase):
+    FILE = {"url": "https://cdn.example.com/mygame-arm64.apk"}
+
+    def test_both_schemas(self):
+        for schema in ("framedrop.install/v1", "frame-control.install/v1"):
+            m = wi.parse_manifest({"schema": schema, "name": "My Game", "files": [dict(self.FILE, sha256="AB" * 32)]})
+            self.assertEqual(m["name"], "My Game")
+            self.assertEqual(m["file"]["url"], self.FILE["url"])
+            self.assertEqual(m["file"]["sha256"], "ab" * 32)
+
+    def test_bad_schema(self):
+        for schema in (None, "framedrop.install/v2", "something"):
+            with self.assertRaises(E, msg=schema):
+                wi.parse_manifest({"schema": schema, "files": [self.FILE]})
+
+    def test_missing_or_bad_fields(self):
+        base = {"schema": "framedrop.install/v1"}
+        for obj in ([], base, dict(base, files=[]), dict(base, files="x"), dict(base, files=[{}]),
+                    dict(base, files=[{"url": ""}]), dict(base, files=[dict(self.FILE, sha256="abc")]),
+                    dict(base, files=[dict(self.FILE, size=-1)]), dict(base, name=5, files=[self.FILE])):
+            with self.assertRaises(E, msg=obj):
+                wi.parse_manifest(obj)
+
+    def test_name_optional_and_cleaned(self):
+        self.assertIsNone(wi.parse_manifest({"schema": "framedrop.install/v1", "files": [self.FILE]})["name"])
+        m = wi.parse_manifest({"schema": "framedrop.install/v1", "name": " A\x1b[31mB\n ", "files": [self.FILE]})
+        self.assertEqual(m["name"], "A[31mB")
+
+    def test_multiple_files_refused_clearly(self):
+        with self.assertRaisesRegex(E, "2 files"):
+            wi.parse_manifest({"schema": "framedrop.install/v1", "files": [self.FILE, self.FILE]})
+
+
+class Stub(BaseHTTPRequestHandler):
+    routes = {}
+
+    def log_message(self, *_):
+        pass
+
+    def do_HEAD(self):
+        self.do_GET(body=False)
+
+    def do_GET(self, body=True):
+        route = self.routes.get(self.path)
+        if route is None:
+            self.send_response(404)
+            self.end_headers()
+            return
+        status, headers, data = route
+        self.send_response(status)
+        for k, v in headers.items():
+            self.send_header(k, v)
+        if "Content-Length" not in headers:
+            self.send_header("Content-Length", str(len(data)))
+        self.end_headers()
+        if body:
+            self.wfile.write(data)
+
+
+class Downloads(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.httpd = ThreadingHTTPServer(("127.0.0.1", 0), Stub)
+        cls.base = f"http://127.0.0.1:{cls.httpd.server_address[1]}"
+        threading.Thread(target=cls.httpd.serve_forever, daemon=True).start()
+        sha = hashlib.sha256(PAYLOAD).hexdigest()
+        Stub.routes = {
+            "/game.apk": (200, {}, PAYLOAD),
+            "/game.zip": (200, {}, PAYLOAD),
+            "/redirect.apk": (302, {"Location": "/game.apk"}, b""),
+            "/to-lan.apk": (302, {"Location": "https://192.168.1.5/game.apk"}, b""),
+            "/to-http.apk": (302, {"Location": "http://cdn.example.com/game.apk"}, b""),
+            "/loop.apk": (302, {"Location": "/loop.apk"}, b""),
+            "/manifest.json": (200, {}, json.dumps({"schema": "framedrop.install/v1", "name": "Stub Game",
+                                                    "files": [{"url": f"{cls.base}/game.apk", "sha256": sha}]}).encode()),
+            "/bad-sha.json": (200, {}, json.dumps({"schema": "frame-control.install/v1", "name": "Bad",
+                                                   "files": [{"url": f"{cls.base}/game.apk", "sha256": "0" * 64}]}).encode()),
+            "/huge.json": (200, {}, b"{" + b" " * (wi.MAX_MANIFEST + 10) + b"}"),
+            "/notjson.json": (200, {}, b"<html>"),
+            "/short.apk": (200, {"Content-Length": str(len(PAYLOAD) + 100)}, PAYLOAD),
+        }
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.httpd.shutdown()
+        cls.httpd.server_close()
+
+    def setUp(self):
+        self.tmp = tempfile.mkdtemp()
+        env = mock.patch.dict(os.environ, {wi.LOCAL_LINKS_ENV: "1"})
+        env.start()
+        self.addCleanup(env.stop)
+
+    def tearDown(self):
+        shutil.rmtree(self.tmp, ignore_errors=True)
+
+    def test_localhost_links_need_the_developer_switch(self):
+        # Without it, a website's link can't make the app fetch from local services.
+        with mock.patch.dict(os.environ, {wi.LOCAL_LINKS_ENV: ""}):
+            for kw in ({"manifest": f"{self.base}/manifest.json"}, {"url": f"{self.base}/game.apk"}):
+                with self.assertRaisesRegex(wi.WebInstallError, wi.LOCAL_LINKS_ENV):
+                    wi.plan(**kw)
+
+    def test_manifest_round_trip(self):
+        p = wi.plan(manifest=f"{self.base}/manifest.json")
+        self.assertEqual((p["name"], p["file"], p["kind"], p["host"], p["size"]),
+                         ("Stub Game", "game.apk", "apk", "127.0.0.1", len(PAYLOAD)))
+        seen = []
+        path = wi.download(p, self.tmp, progress=lambda done, total: seen.append((done, total)))
+        self.assertEqual(Path(path).read_bytes(), PAYLOAD)
+        self.assertEqual(seen[-1], (len(PAYLOAD), len(PAYLOAD)))
+        self.assertEqual(os.listdir(self.tmp), ["game.apk"])
+
+    def test_direct_url_and_redirect(self):
+        p = wi.plan(url=f"{self.base}/redirect.apk")
+        self.assertEqual((p["name"], p["file"]), ("redirect.apk", "redirect.apk"))
+        self.assertEqual(Path(wi.download(p, self.tmp)).read_bytes(), PAYLOAD)
+
+    def test_redirects_checked_again(self):
+        for path in ("/to-lan.apk", "/to-http.apk", "/loop.apk"):
+            with self.assertRaises(E, msg=path):
+                wi._open(f"{self.base}{path}", allow_local=True)
+
+    def test_sha256_mismatch_leaves_nothing(self):
+        p = wi.plan(manifest=f"{self.base}/bad-sha.json")
+        with self.assertRaisesRegex(E, "sha256"):
+            wi.download(p, self.tmp)
+        self.assertEqual(os.listdir(self.tmp), [])
+
+    def test_size_cap(self):
+        with mock.patch.object(wi, "MAX_FILE", 1000):
+            with self.assertRaisesRegex(E, "limit"):
+                wi.plan(url=f"{self.base}/game.apk")
+            p = {"url": f"{self.base}/game.apk", "file": "game.apk", "allowLocal": True, "size": None, "sha256": None}
+            with self.assertRaisesRegex(E, "limit"):
+                wi.download(p, self.tmp)
+        self.assertEqual(os.listdir(self.tmp), [])
+
+    def test_bad_manifests(self):
+        for path in ("/huge.json", "/notjson.json", "/missing.json"):
+            with self.assertRaises(E, msg=path):
+                wi.plan(manifest=f"{self.base}{path}")
+
+    def test_cut_off_download(self):
+        p = {"url": f"{self.base}/short.apk", "file": "short.apk", "allowLocal": True, "size": None, "sha256": None}
+        with self.assertRaises(E):
+            wi.download(p, self.tmp)
+        self.assertEqual(os.listdir(self.tmp), [])
+
+    def test_aborted_connection_never_connects(self):
+        port = self.httpd.server_address[1]
+        for cls in (wi._HTTPConnection, wi._HTTPSConnection):
+            conn = cls("127.0.0.1", "127.0.0.1", port, 5)
+            wi.abort(conn)  # before connect, e.g. cancelled while looking up the name
+            with self.assertRaisesRegex(OSError, "aborted"):
+                conn.connect()
+
+    def test_cancel(self):
+        p = wi.plan(url=f"{self.base}/game.apk")
+        with self.assertRaises(wi.Cancelled):
+            wi.download(p, self.tmp, cancelled=lambda: True)
+        self.assertEqual(os.listdir(self.tmp), [])
+
+
+class Dispatch(unittest.TestCase):
+    def setUp(self):
+        self.tmp = tempfile.mkdtemp()
+
+    def tearDown(self):
+        shutil.rmtree(self.tmp, ignore_errors=True)
+
+    def file(self, name):
+        path = os.path.join(self.tmp, name)
+        Path(path).write_bytes(PAYLOAD)
+        return path
+
+    def test_apk_goes_to_the_android_installer(self):
+        import frame_android
+        with mock.patch.object(frame_android, "install", return_value={"label": "Stub"}) as install:
+            res = wi.dispatch(self.file("game.apk"), name="Ignored", source="https://example.com/game.apk")
+        install.assert_called_once_with(os.path.join(self.tmp, "game.apk"), source="https://example.com/game.apk")
+        self.assertEqual(res["kind"], "apk")
+        self.assertIn("Stub", res["message"])
+
+    def test_titles_without_the_titles_module(self):
+        with mock.patch.dict(sys.modules, {"frame_titles": None}):
+            with self.assertRaisesRegex(E, "newer Frame Control"):
+                wi.dispatch(self.file("game.zip"))
+
+    def test_titles_go_to_frame_titles(self):
+        fake = mock.Mock()
+        fake.install.return_value = {"message": "Installed Stub"}
+        with mock.patch.dict(sys.modules, {"frame_titles": fake}):
+            res = wi.dispatch(self.file("game.exe"), name="Stub", exe=None)
+        fake.install.assert_called_once_with(os.path.join(self.tmp, "game.exe"), name="Stub", exe=None, progress=None)
+        self.assertEqual(res["message"], "Installed Stub")
+
+    def test_other_files_refused(self):
+        with self.assertRaises(E):
+            wi.dispatch(self.file("game.sh"))
+
+
+class ServerJobs(unittest.TestCase):
+    """The server's install worker (ui/server.py), with download and dispatch stubbed."""
+
+    @classmethod
+    def setUpClass(cls):
+        with mock.patch.dict(os.environ, {"FRAME_ALIAS": "frame-control-test.invalid"}):
+            import server
+        cls.server = server
+
+    def run_job(self, download=None, mkdtemp_error=None):
+        s = self.server
+        job = {"phase": "download", "done": 0, "total": None, "detail": "", "message": None, "error": None, "cancel": False}
+        plan = {"name": "Stub", "exe": None, "url": "https://example.com/stub.apk"}
+        with mock.patch.object(s, "ensure_master"), \
+                mock.patch.object(s.frame_webinstall, "download", side_effect=lambda *a, **k: download(job, a[1])), \
+                mock.patch.object(s.tempfile, "mkdtemp", side_effect=mkdtemp_error or tempfile.mkdtemp), \
+                mock.patch.object(s.frame_webinstall, "dispatch", return_value={"message": "ok"}) as dispatch:
+            s._webinstall_run(plan, job)
+        return job, dispatch
+
+    def test_cancel_after_the_last_chunk_still_stops_the_install(self):
+        def download(job, tmp):
+            job["cancel"] = True  # arrives after the downloader's last check
+            return os.path.join(tmp, "stub.apk")
+        job, dispatch = self.run_job(download)
+        dispatch.assert_not_called()
+        self.assertEqual(job["phase"], "error")
+
+    def test_finished_download_is_dispatched(self):
+        job, dispatch = self.run_job(lambda job, tmp: os.path.join(tmp, "stub.apk"))
+        dispatch.assert_called_once()
+        self.assertEqual((job["phase"], job["message"]), ("done", "ok"))
+
+    def stall_then_shutdown(self, scheme, reply):
+        if os.name == "nt":
+            # shutdown() from another thread doesn't wake a blocked recv on Windows, and
+            # closing the handle under a TLS read isn't safe; see web-install.md.
+            self.skipTest("Windows: a stalled download is only dropped when the app stops the server")
+        """Start a download from a server that stalls after sending reply; shutdown must stop it quickly."""
+        stall = socket.socket()
+        stall.bind(("127.0.0.1", 0))
+        stall.listen(1)
+        port = stall.getsockname()[1]
+        stalled = threading.Event()
+
+        def serve():
+            c, _ = stall.accept()
+            if reply is not None:
+                c.recv(65536)
+                c.sendall(reply)
+            stalled.set()
+            time.sleep(20)  # longer than the test may take; TIMEOUT is 30 s
+            c.close()
+        threading.Thread(target=serve, daemon=True).start()
+        s = self.server
+        pid = "shutdown-test"
+        s._web_plans[pid] = {"name": "Stub", "exe": None, "url": f"{scheme}://127.0.0.1:{port}/stub.apk",
+                             "file": "stub.apk", "allowLocal": True, "size": None, "sha256": None,
+                             "sizeFromManifest": False}
+        try:
+            s.webinstall_start({"id": pid})
+            job = s._web_jobs[pid]
+            self.assertTrue(stalled.wait(5))
+            time.sleep(0.1)  # let the client block
+            t0 = time.time()
+            s.webinstall_shutdown()
+            self.assertLess(time.time() - t0, 3)
+            self.assertEqual(s._web_workers, set())
+            self.assertEqual((job["phase"], job["error"]), ("error", "download cancelled"))
+            s._web_plans["late"] = {"size": None}
+            with self.assertRaises(s.Failure) as caught:  # nothing new starts once quitting
+                s.webinstall_start({"id": "late"})
+            self.assertEqual(caught.exception.status, 503)
+        finally:
+            s._web_closing = False
+            s._web_jobs.clear()
+            s._web_plans.clear()
+            stall.close()
+
+    def test_shutdown_interrupts_a_stalled_body(self):
+        self.stall_then_shutdown("http", b"HTTP/1.0 200 OK\r\nContent-Length: 1000000\r\n\r\npartial")
+
+    def test_shutdown_interrupts_stalled_headers(self):
+        self.stall_then_shutdown("http", b"HTTP/1.1 200 OK\r\n")
+
+    def test_shutdown_interrupts_a_stalled_tls_handshake(self):
+        self.stall_then_shutdown("https", None)
+
+    def test_dead_servers_leftovers_swept(self):
+        dead = subprocess.Popen([sys.executable, "-c", "pass"])
+        dead.wait()
+        # Downloads and title staging (unzipped titles) are both swept.
+        for prefix in (self.server.WEB_TMP_PREFIX, self.server.frame_titles.TMP_PREFIX):
+            gone = tempfile.mkdtemp(prefix=f"{prefix}{dead.pid}-")
+            live = tempfile.mkdtemp(prefix=f"{prefix}{os.getpid()}-")
+            try:
+                self.server.sweep_tmp()
+                self.assertFalse(os.path.exists(gone), prefix)
+                self.assertTrue(os.path.exists(live), prefix)
+            finally:
+                shutil.rmtree(gone, ignore_errors=True)
+                shutil.rmtree(live, ignore_errors=True)
+
+    def test_temp_dir_failure_ends_the_job(self):
+        job, dispatch = self.run_job(mkdtemp_error=OSError("disk full"))
+        dispatch.assert_not_called()
+        self.assertEqual(job["phase"], "error")
+        self.assertIn("disk full", job["error"])
+
+
+@unittest.skipUnless(shutil.which("node"), "needs node")
+class LinkParsing(unittest.TestCase):
+    def parse(self, links):
+        script = ("const { parseInstallLink, linkFromArgv } = require(process.argv[1]);"
+                  "const links = JSON.parse(process.argv[2]);"
+                  "console.log(JSON.stringify({ parsed: links.map(parseInstallLink),"
+                  " argv: linkFromArgv(['/x/frame-control', '--flag', links[0]]) }));")
+        out = subprocess.run(["node", "-e", script, str(ROOT / "app" / "install-link.js"), json.dumps(links)],
+                             capture_output=True, text=True, timeout=30)
+        self.assertEqual(out.returncode, 0, out.stderr)
+        return json.loads(out.stdout)
+
+    def test_links(self):
+        m = "https://example.com/m.json"
+        good = ["frame-control://install?manifest=" + "https%3A%2F%2Fexample.com%2Fm.json",
+                "frame-control://install/?url=https%3A%2F%2Fcdn.example.com%2Fg.apk",
+                "FRAME-CONTROL://install?manifest=http%3A%2F%2Flocalhost%3A8000%2Fm.json"]
+        bad = ["framedrop://install?manifest=" + m, "frame-control://uninstall?manifest=" + m,
+               "frame-control://install?manifest=" + m + "&url=" + m, "frame-control://install?manifest=a&manifest=b",
+               "frame-control://install?manifest=file%3A%2F%2F%2Fetc%2Fpasswd", "frame-control://install?other=" + m,
+               "frame-control://install?url=https%3A%2F%2Fu%3Ap%40example.com%2Fg.apk", "frame-control://install",
+               "frame-control://install/sub?url=" + m, "https://example.com"]
+        res = self.parse(good + bad)
+        self.assertEqual(res["parsed"][0], {"kind": "manifest", "target": m})
+        self.assertEqual(res["parsed"][1], {"kind": "url", "target": "https://cdn.example.com/g.apk"})
+        self.assertEqual(res["parsed"][2]["kind"], "manifest")
+        self.assertEqual(res["parsed"][len(good):], [None] * len(bad))
+        self.assertEqual(res["argv"], good[0])
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/ui/frame_apk.py b/ui/frame_apk.py
index 53fd58a..943af2a 100644
--- a/ui/frame_apk.py
+++ b/ui/frame_apk.py
@@ -12,6 +12,13 @@ import zipfile
 ATTR = {0x01010001: 'label', 0x01010002: 'icon', 0x01010003: 'name',
         0x0101021b: 'versionCode', 0x0101021c: 'versionName', 0x0101020c: 'minSdkVersion'}
 T_REF, T_STRING, T_INT_DEC, T_INT_HEX = 0x01, 0x03, 0x10, 0x11
+# APKs can come from websites (install links), so nothing read from one may be
+# unbounded. zipfile stops at a member's declared size, so checking it is enough.
+MAX_MANIFEST = 16 * 1024**2
+MAX_ARSC = 128 * 1024**2      # real ones are a few MB; the largest apps' tens of MB
+MAX_ICON = 8 * 1024**2
+MAX_VALUES = 256              # resolved values per reference, across all its hops
+MAX_STEPS = 4096              # entries examined per reference, dead ends and cycles included
 
 
 class ApkError(Exception):
@@ -129,15 +136,23 @@ class Resources:
                 resid = (pid << 24) | (tid << 16) | index
                 self.entries.setdefault(resid, []).append((language, density, dtype, value))
 
-    def values(self, resid, depth=0):
-        """[(language, density, type, data)] with references followed."""
+    def values(self, resid, depth=0, seen=frozenset(), steps=None):
+        """[(language, density, type, data)] with references followed: never round a
+        cycle, at most MAX_VALUES results and MAX_STEPS entries examined in all."""
+        steps = steps if steps is not None else [MAX_STEPS]
         out = []
+        seen = seen | {resid}
         for lang, dens, dtype, value in self.entries.get(resid, []):
+            steps[0] -= 1
+            if steps[0] < 0 or len(out) >= MAX_VALUES:
+                break
             if dtype == T_REF and depth < 5:
-                out += [(lang or l2, dens or d2, t2, v2) for l2, d2, t2, v2 in self.values(value, depth + 1)]
+                if value not in seen:
+                    out += [(lang or l2, dens or d2, t2, v2)
+                            for l2, d2, t2, v2 in self.values(value, depth + 1, seen, steps)]
             else:
                 out.append((lang, dens, dtype, value))
-        return out
+        return out[:MAX_VALUES]
 
     def string(self, dtype, value):
         return self.strings[value] if dtype == T_STRING and value < len(self.strings) else None
@@ -171,6 +186,24 @@ def _icons(attr, res):
     return [s for _, s in sorted(vals, key=lambda x: -x[0]) if s]
 
 
+def _read(z, name, limit):
+    """A member's bytes, inflating at most limit + 1 of them whatever its header claims
+    (ZipFile.read inflates everything first, then trims to the declared size)."""
+    info = z.getinfo(name)
+    # Android only reads stored and deflated entries, and only those bound what
+    # a read inflates (Python 3.9's bzip2 and lzma readers don't).
+    if info.compress_type not in (zipfile.ZIP_STORED, zipfile.ZIP_DEFLATED):
+        raise ApkError(f'{name} in the APK uses a compression Android does not')
+    size = info.file_size
+    if size > limit:
+        raise ApkError(f'{name} in the APK is {size / 1024**2:.0f} MB, more than a real one ({limit // 1024**2} MB)')
+    with z.open(name) as f:
+        data = f.read(limit + 1)
+    if len(data) > limit:
+        raise ApkError(f'{name} in the APK is larger than a real one ({limit // 1024**2} MB)')
+    return data
+
+
 def apk_info(path):
     """Package, label, version, min_sdk, abis and the best PNG icon inside the APK."""
     try:
@@ -182,8 +215,8 @@ def apk_info(path):
         if 'AndroidManifest.xml' not in names:
             raise ApkError('not an APK: no AndroidManifest.xml')
         try:
-            elements = manifest_elements(z.read('AndroidManifest.xml'))
-            res = Resources(z.read('resources.arsc') if 'resources.arsc' in names else b'')
+            elements = manifest_elements(_read(z, 'AndroidManifest.xml', MAX_MANIFEST))
+            res = Resources(_read(z, 'resources.arsc', MAX_ARSC) if 'resources.arsc' in names else b'')
         except (struct.error, IndexError, zipfile.BadZipFile) as e:
             raise ApkError(f'could not read the APK manifest: {e}')
         tags = {}
@@ -212,11 +245,11 @@ def apk_info(path):
 def _icon_png(z, names, icons):
     for icon in icons:
         if icon.endswith('.png') and icon in names:
-            return z.read(icon)
+            return _read(z, icon, MAX_ICON)
     # Adaptive icons are XML; fall back to the largest launcher PNG.
     pngs = sorted((n for n in names if n.endswith('.png') and 'ic_launcher' in n and 'foreground' not in n),
                   key=lambda n: z.getinfo(n).file_size)
-    return z.read(pngs[-1]) if pngs else None
+    return _read(z, pngs[-1], MAX_ICON) if pngs else None
 
 
 if __name__ == '__main__':
diff --git a/ui/frame_connect.py b/ui/frame_connect.py
index bdf93ec..9b75ded 100644
--- a/ui/frame_connect.py
+++ b/ui/frame_connect.py
@@ -1,29 +1,41 @@
-"""Connect this computer to the Steam Frame: find it, create a key, add a `Host frame`
-alias to ~/.ssh/config and copy the key over, asking for the Developer Mode
-password once. The Linux and Windows twin of scripts/connect.sh (which the Mac
-app uses); same config block, so either can re-run over the other. Idempotent.
+"""Connect this computer to the Steam Frame: find it, create keys, add a `Host frame`
+alias to ~/.ssh/config and get a key onto the headset. It first asks Valve's
+SteamOS devkit service (port 32000) to pair, which needs only a tap on the
+headset; if that service isn't there or says no, it copies the key over SSH,
+asking for the Developer Mode password once. The Linux and Windows twin of
+scripts/connect.sh (which the Mac app uses); same config block, so either can
+re-run over the other. Idempotent.
 
 Usage: python3 ui/frame_connect.py [HOST_OR_IP[:PORT]]
 Env:   FRAME_USER (default steamos), FRAME_ALIAS (default frame)
 """
 import base64
+import json
 import os
 import platform
 import re
+import shutil
 import socket
 import subprocess
 import sys
 import time
+import urllib.error
+import urllib.request
 from pathlib import Path
 
 FRAME_USER = os.environ.get("FRAME_USER", "steamos")
+USER_FROM_ENV = "FRAME_USER" in os.environ
 FRAME_ALIAS = os.environ.get("FRAME_ALIAS", "frame")
 SSH_DIR = Path.home() / ".ssh"
 KEY = SSH_DIR / "id_ed25519_frame"
+# The devkit service only accepts ssh-rsa keys (write_key in Valve's
+# steamos-devkit-service), so pairing uses a second key next to the ed25519 one.
+DEVKIT_KEY = SSH_DIR / "id_rsa_frame_devkit"
 CONFIG = SSH_DIR / "config"
+NAME_RE = re.compile(r"[A-Za-z0-9][A-Za-z0-9._-]*")
 # Both go into ~/.ssh/config, so nothing that could add a line or a directive.
 for _name, _value in (("FRAME_ALIAS", FRAME_ALIAS), ("FRAME_USER", FRAME_USER)):
-    if not re.fullmatch(r"[A-Za-z0-9][A-Za-z0-9._-]*", _value):
+    if not NAME_RE.fullmatch(_value):
         sys.exit(f"{_name} must be a plain name, not {_value!r}")
 BEGIN = f"# >>> steam-frame ({FRAME_ALIAS}) >>>"
 END = f"# <<< steam-frame ({FRAME_ALIAS}) <<<"
@@ -42,6 +54,108 @@ def say(msg):
     print(msg, flush=True)
 
 
+# --- Valve's SteamOS devkit pairing (steamos-devkit-service on the headset). HTTP on
+# port 32000: GET /properties.json names the user to log in as; POST /register with
+# "ssh-rsa <key> <comment> <magic>" shows an approve prompt in the headset (the
+# comment is what it displays, 30 s to answer), then installs the key and turns sshd on.
+# The prompt only appears while Steam is on Settings > Developer > Pair new host;
+# otherwise /register answers 403 "please put the Steam client in pairing mode".
+
+DEVKIT_PORT = 32000
+DEVKIT_SERVICE = "_steamos-devkit._tcp"
+MAGIC_PHRASE = "900b919520e4cf601998a71eec318fec"  # fixed token Valve's client appends
+REGISTER_TIMEOUT = 60
+PAIRING_MODE_WAIT = 120  # seconds to keep asking while the user opens "Pair new host"
+# A LAN host: never go through an HTTP(S)_PROXY from the environment.
+_opener = urllib.request.build_opener(urllib.request.ProxyHandler({}))
+
+
+def key_comment(node):
+    """"frame-control@<short host name>" as one word: the headset splits the body on spaces."""
+    name = re.sub(r"[^A-Za-z0-9._-]+", "-", (node or "").split(".")[0]).strip("-.") or "computer"
+    return f"frame-control@{name}"
+
+
+def register_body(pub, comment):
+    fields = pub.split()
+    if len(fields) < 2 or fields[0] != "ssh-rsa":
+        raise ValueError("the devkit service only takes ssh-rsa keys")
+    return f"ssh-rsa {fields[1]} {comment} {MAGIC_PHRASE}\n"
+
+
+def parse_login(raw):
+    """The `login` from /properties.json if it's a plain user name, else None. "root"
+    means several users are configured and Valve's client switches between them; we
+    can't, so it counts as no answer."""
+    props = json.loads(raw)
+    if not isinstance(props, dict):
+        raise ValueError("properties.json isn't a JSON object")
+    login = props.get("login")
+    if isinstance(login, str) and NAME_RE.fullmatch(login) and login != "root":
+        return login
+    return None
+
+
+def devkit_error(status, raw):
+    """A readable reason from a failed /register: its {"error": ...} JSON, or the text."""
+    text = raw.decode("utf-8", "replace").strip()
+    try:
+        err = json.loads(text).get("error")
+    except (ValueError, AttributeError):
+        err = None
+    return str(err or text or f"HTTP {status}")[:300]
+
+
+def devkit_url(host, port, path):
+    return f"http://[{host}]:{port}{path}" if ":" in host else f"http://{host}:{port}{path}"
+
+
+def why(e):
+    return str(getattr(e, "reason", None) or e)
+
+
+def fetch_login(host, port=DEVKIT_PORT, timeout=5):
+    """GET /properties.json. Raises OSError (HTTP errors included) or ValueError."""
+    with _opener.open(devkit_url(host, port, "/properties.json"), timeout=timeout) as r:
+        return parse_login(r.read())
+
+
+def register(host, body, port=DEVKIT_PORT, timeout=REGISTER_TIMEOUT):
+    """POST /register, which waits while someone answers the prompt. -> (ok, message)"""
+    req = urllib.request.Request(devkit_url(host, port, "/register"), data=body.encode("ascii"),
+                                 headers={"Content-Type": "text/plain"}, method="POST")
+    try:
+        with _opener.open(req, timeout=timeout) as r:
+            return True, r.read().decode("utf-8", "replace").strip()
+    except urllib.error.HTTPError as e:
+        with e:
+            return False, devkit_error(e.code, e.read())
+    except OSError as e:
+        return False, f"no answer ({why(e)})"
+
+
+def devkit_pair(host, pub, comment, port=DEVKIT_PORT, on_login=None):
+    """The password-free route. -> None once paired, else the reason, which means: fall
+    back to copying the key with the password. on_login(user) runs before the prompt
+    with the login properties.json names, so the fallback uses that user too."""
+    try:
+        login = fetch_login(host, port)
+    except (OSError, ValueError) as e:
+        return f"devkit service not reachable on port {port}: {why(e)}"
+    if login and on_login:
+        on_login(login)
+    say("    In the headset: Steam Settings > Developer > Pair new host, then approve the request")
+    body = register_body(pub, comment)
+    ok, msg = register(host, body, port)
+    # The headset refuses at once unless Steam is on its "Pair new host" screen
+    # (verified on a Frame, 2026-09-26), so keep asking while the user opens it.
+    deadline = time.monotonic() + PAIRING_MODE_WAIT
+    while not ok and "pairing mode" in msg and time.monotonic() < deadline:
+        time.sleep(3)
+        ok, msg = register(host, body, port)
+    return None if ok else f"devkit pairing failed: {msg}"
+
+
 def split_port(arg):
     """"host:2222" -> ("host", 2222); anything else (IPv6 too) keeps port 22."""
     host, sep, port = arg.rpartition(":")
@@ -58,6 +172,70 @@ def port_open(host, port=22):
         return False
 
 
+def reachable(host, port):
+    """sshd, or the devkit service, which turns sshd on once a pairing is approved."""
+    try:
+        socket.getaddrinfo(host, port, type=socket.SOCK_STREAM)
+    except OSError:
+        return False
+    return port_open(host, port) or port_open(host, DEVKIT_PORT)
+
+
+# --- mDNS. There's no stdlib client, so this borrows dns-sd (macOS; Bonjour for
+# Windows) or avahi-browse (Linux) when present, with short timeouts.
+
+def run_for(args, seconds):
+    """What a command printed within `seconds`; dns-sd never exits by itself."""
+    try:
+        out = subprocess.run(args, capture_output=True, timeout=seconds).stdout
+    except subprocess.TimeoutExpired as e:
+        out = e.stdout
+    except OSError:
+        out = b""
+    return (out or b"").decode("utf-8", "replace")
+
+
+def parse_dns_sd_browse(text):
+    """Instance names from `dns-sd -B _steamos-devkit._tcp`, deduplicated, in order."""
+    pat = re.compile(r"\sAdd\s+\d+\s+\d+\s+\S+\s+" + re.escape(DEVKIT_SERVICE) + r"\.\s+(.+?)\s*$")
+    names = []
+    for line in text.splitlines():
+        m = pat.search(line)
+        if m and m.group(1) not in names:
+            names.append(m.group(1))
+    return names
+
+
+def parse_dns_sd_resolve(text):
+    """The target host from `dns-sd -L` ("... can be reached at frame.local.:32000")."""
+    m = re.search(r"can be reached at (\S+?)\.?:\d+", text)
+    return m.group(1) if m else None
+
+
+def parse_avahi(text):
+    """Host names, then IPv4 addresses, from `avahi-browse -rpt` resolved ("=") lines."""
+    names, addrs = [], []
+    for line in text.splitlines():
+        f = line.split(";")
+        if len(f) >= 9 and f[0] == "=" and f[2] == "IPv4":
+            names.append(f[6])
+            addrs.append(f[7])
+    return list(dict.fromkeys(names + addrs))
+
+
+def discover_devkit():
+    if shutil.which("dns-sd"):
+        hosts = []
+        for name in parse_dns_sd_browse(run_for(["dns-sd", "-B", DEVKIT_SERVICE, "local."], 3))[:4]:
+            host = parse_dns_sd_resolve(run_for(["dns-sd", "-L", name, DEVKIT_SERVICE, "local."], 2))
+            if host and host not in hosts:
+                hosts.append(host)
+        return hosts
+    if shutil.which("avahi-browse"):
+        return parse_avahi(run_for(["avahi-browse", "-rpt", DEVKIT_SERVICE], 5))
+    return []
+
+
 HOST_RE = re.compile(r"[A-Za-z0-9][A-Za-z0-9.:%-]*")
 
 
@@ -67,9 +245,16 @@ def pick_host(arg):
         return None
     for cand in [arg] if arg else [f"{FRAME_ALIAS}.local", FRAME_ALIAS]:
         host, port = split_port(cand)
-        if port_open(host, port):
+        if reachable(host, port):
             return host, port
-        say(f"  - {cand}: not resolvable or port {port} closed")
+        say(f"  - {cand}: not resolvable, or ports {port} and {DEVKIT_PORT} closed")
+    if arg:
+        return None
+    say(f"  - asking mDNS for {DEVKIT_SERVICE}")
+    for host in discover_devkit():
+        if HOST_RE.fullmatch(host) and reachable(host, 22):
+            return host, 22
+        say(f"  - {host}: advertised, but not reachable")
     return None
 
 
@@ -82,7 +267,23 @@ def make_ssh_dir():
         SSH_DIR.mkdir(mode=0o700, exist_ok=True)
 
 
-def write_config(host, port=22):
+def make_key(path, kind, comment):
+    if path.exists():
+        say(f"    exists: {path}")
+        return
+    bits = ["-b", "3072"] if kind == "rsa" else []
+    subprocess.run(["ssh-keygen", "-q", "-t", kind, *bits, "-N", "", "-C", comment, "-f", str(path)], check=True)
+    say(f"    created {path}")
+
+
+def config_block(host, port=22, user=FRAME_USER):
+    return [BEGIN, f"Host {FRAME_ALIAS}", f"  HostName {host}", *([f"  Port {port}"] if port != 22 else []),
+            f"  User {user}",
+            "  IdentityFile ~/.ssh/id_ed25519_frame", "  IdentityFile ~/.ssh/id_rsa_frame_devkit",
+            "  IdentitiesOnly yes", "  ServerAliveInterval 30", "Host *", END]
+
+
+def write_config(host, port=22, user=FRAME_USER):
     """Replace our managed block and put it first: ssh uses the first value it sees per
     option. The trailing "Host *" returns the rest of the file to global scope."""
     make_ssh_dir()
@@ -95,10 +296,7 @@ def write_config(host, port=22):
             skip = False
         elif not skip:
             kept.append(line)
-    block = [BEGIN, f"Host {FRAME_ALIAS}", f"  HostName {host}", *([f"  Port {port}"] if port != 22 else []),
-             f"  User {FRAME_USER}",
-             "  IdentityFile ~/.ssh/id_ed25519_frame", "  IdentitiesOnly yes",
-             "  ServerAliveInterval 30", "Host *", END]
+    block = config_block(host, port, user)
     tmp = CONFIG.with_name("config.frame-control.tmp")
     tmp.write_text("\n".join(block + kept) + "\n", encoding="utf-8")
     if os.name != "nt":
@@ -125,6 +323,50 @@ def key_login_works():
                           capture_output=True).returncode == 0
 
 
+def configured_user():
+    """The User in our managed block, so a re-run keeps one the headset named earlier."""
+    if not CONFIG.exists():
+        return None
+    inside = False
+    for line in CONFIG.read_text(encoding="utf-8").splitlines():
+        if line in (BEGIN, END):
+            inside = line == BEGIN
+        elif inside and line.startswith("  User "):
+            name = line[7:].strip()
+            return name if NAME_RE.fullmatch(name) else None
+    return None
+
+
+def pair_with_devkit(host, port, user):
+    """Try devkit pairing and confirm key login. -> (user, None) or (user, reason to fall back)."""
+    say("==> Pairing through the headset's SteamOS devkit service (no password)")
+    chosen = [user]
+
+    def use_login(login):
+        if login == chosen[0]:
+            return
+        if USER_FROM_ENV:
+            say(f"    the headset logs in as '{login}'; keeping FRAME_USER={user}")
+        else:
+            chosen[0] = login
+            say(f"    the headset logs in as '{login}'")
+            write_config(host, port, login)
+
+    try:
+        pub = DEVKIT_KEY.with_suffix(".pub").read_text(encoding="utf-8")
+    except OSError as e:
+        return user, f"can't read the pairing key: {e}"
+    reason = devkit_pair(host, pub, key_comment(platform.node()), on_login=use_login)
+    if reason:
+        return chosen[0], reason
+    # The approval is what turns sshd on, so it may take a moment to answer.
+    for _ in range(10):
+        if key_login_works():
+            return chosen[0], None
+        time.sleep(1)
+    return chosen[0], "paired, but key login still fails"
+
+
 def main(argv):
     if argv and argv[0] in ("-h", "--help"):
         sys.exit(__doc__)
@@ -143,30 +385,32 @@ def main(argv):
     host, port = found
     say(f"    found: {host}" + (f" port {port}" if port != 22 else ""))
 
-    say("==> SSH key")
+    say("==> SSH keys")
     make_ssh_dir()
-    if KEY.exists():
-        say(f"    exists: {KEY}")
-    else:
-        subprocess.run(["ssh-keygen", "-q", "-t", "ed25519", "-N", "", "-C",
-                        f"{platform.node() or 'computer'}->steam-frame", "-f", str(KEY)], check=True)
-        say(f"    created {KEY}")
+    make_key(KEY, "ed25519", f"{platform.node() or 'computer'}->steam-frame")
+    make_key(DEVKIT_KEY, "rsa", key_comment(platform.node()))
 
+    user = FRAME_USER if USER_FROM_ENV else (configured_user() or FRAME_USER)
     say(f"==> ~/.ssh/config alias '{FRAME_ALIAS}' -> {host}")
-    write_config(host, port)
+    write_config(host, port, user)
 
     say("==> Checking key login")
     if key_login_works():
         say("    key login already works")
     else:
-        say("    copying the key: enter the Developer Mode password when asked")
-        pub = KEY.with_suffix(".pub").read_text(encoding="utf-8").strip()
-        r = subprocess.run(["ssh", "-o", "StrictHostKeyChecking=accept-new", "-o", "PubkeyAuthentication=no",
-                            "-p", str(port), f"{FRAME_USER}@{host}", ADD_KEY_CMD], input=pub + "\n", text=True)
-        if r.returncode != 0 or not key_login_works():
-            say("Key login still isn't working. Check the password and run this again.")
-            return 1
-        say("    key login OK")
+        user, reason = pair_with_devkit(host, port, user)
+        if not reason:
+            say("    paired; key login OK")
+        else:
+            say(f"    {reason}; falling back to the password")
+            say("    copying the key: enter the Developer Mode password when asked")
+            pub = KEY.with_suffix(".pub").read_text(encoding="utf-8").strip()
+            r = subprocess.run(["ssh", "-o", "StrictHostKeyChecking=accept-new", "-o", "PubkeyAuthentication=no",
+                                "-p", str(port), f"{user}@{host}", ADD_KEY_CMD], input=pub + "\n", text=True)
+            if r.returncode != 0 or not key_login_works():
+                say("Key login still isn't working. Check the password and run this again.")
+                return 1
+            say("    key login OK")
     say(f"\nDone. Frame Control can reach the Frame now. In a terminal: ssh {FRAME_ALIAS}")
     return 0
 
diff --git a/ui/frame_titles.py b/ui/frame_titles.py
new file mode 100644
index 0000000..bff6b56
--- /dev/null
+++ b/ui/frame_titles.py
@@ -0,0 +1,819 @@
+"""Linux and Windows builds on the Frame as Steam "Devkit Games".
+
+A .zip, a folder or a single executable becomes a title in the Steam library,
+through the same path as Valve's SteamOS Devkit Client: its devkit-utils
+(vendored in frame/devkit-utils, synced to ~/devkit-utils on the Frame) make
+~/devkit-game/<id>/, the files are copied there, and steam-client-create-shortcut
+asks the running Steam client to register it with a runtime:
+
+  Windows .exe      -> Proton Experimental (steam_play=1; x86-64 runs through FEX)
+  aarch64 ELF       -> Steam Linux Runtime 4.0 ARM64 (steam_play=0)
+  x86-64 ELF        -> Steam Linux Runtime 4.0 (steam_play=0; runs through FEX)
+
+Everything device-side is inferred from Valve's steamos-devkit source until
+checked on a headset; see docs/sideloading.md.
+
+Python stdlib only. CLI:
+  python3 ui/frame_titles.py inspect PATH
+  python3 ui/frame_titles.py install PATH [--name N] [--exe REL] [--runtime R]
+  python3 ui/frame_titles.py list | launch ID | remove ID
+"""
+import hashlib, json, os, posixpath, re, shlex, shutil, stat, struct, subprocess, sys, tempfile, threading, time, zipfile
+
+import frame_android
+import frame_host
+from frame_android import FrameError
+
+ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+UTILS_LOCAL = os.path.join(ROOT, 'frame', 'devkit-utils')
+UTILS = 'devkit-utils'                    # on the Frame, relative to $HOME (where Valve's client puts it)
+GAMES = 'devkit-game'                     # ditto; steamos-prepare-upload makes <id>/ in here
+STAMP = '.frame-control-stamp'
+PY = 'python3 ~/' + UTILS + '/'
+
+# Valve's reserved sideload names: uploading one of these replaces the Steam client itself.
+# devkit-steam is the trampoline file that switches SteamOS to a sideloaded client
+# (select_steam.sh); a folder there breaks Valve's devkit tools.
+RESERVED_IDS = ('steam', 'steamdeckard', 'steamvr', 'steamvrdeckard', 'devkit-steam')
+ID_RE = re.compile(r'^[A-Za-z0-9][A-Za-z0-9_-]{0,63}$')
+DIR_RE = re.compile(r'^/[A-Za-z0-9_./-]+$')
+
+# Zip limits: well above any real game, well below a zip bomb.
+MAX_UNPACKED = 64 * 1024**3
+MAX_ENTRIES = 200000
+TMP_PREFIX = 'frame-title-'  # then the server's PID, so server.sweep_tmp can clear a killed run's
+MAX_RATIO = 200                           # uncompressed / compressed, once past 1 GB
+
+# The Steam compat tool aliases Valve's client uses (devkit_client RUNTIME_ALIASES).
+RUNTIMES = {
+    'proton-experimental': {'label': 'Proton Experimental', 'steam_play': True},
+    'proton-stable': {'label': 'Proton (stable)', 'steam_play': True},
+    'SteamLinuxRuntime_4-arm64': {'label': 'Steam Linux Runtime 4.0 (ARM64)', 'steam_play': False},
+    'SteamLinuxRuntime_4': {'label': 'Steam Linux Runtime 4.0 (x86-64, through FEX)', 'steam_play': False},
+}
+# Experimental rather than stable: the Frame's ARM64 Proton + FEX stack is new,
+# and Proton fixes reach Experimental first. --runtime proton-stable switches.
+DEFAULT_PROTON = 'proton-experimental'
+
+ELF_MACHINES = {0xB7: 'arm64', 0x3E: 'x86_64', 0x03: 'x86', 0x28: 'arm'}
+PE_MACHINES = {0x8664: 'x86_64', 0xAA64: 'arm64', 0x14C: 'x86', 0x1C4: 'arm'}
+# Executables that are never the game: crash reporters, installers, redistributables.
+SKIP_RE = re.compile(r'crash|unins|setup|install|redist|dxsetup|dxwebsetup|dotnet|prereq|'
+                     r'easyanticheat|eac_|updater|uploader|report|sandbox|helper', re.I)
+SKIP_DIRS = re.compile(r'^(_*commonredist|redist|redistributables?|directx|vcredist|__installer|'
+                       r'installers?|prereqs?|support|engine|__macosx)$', re.I)
+# Trailing words of an archive name that describe the build, not the game.
+BUILD_WORDS = re.compile(r'([ ._-]+(win(dows)?(32|64)?|linux(32|64)?|x64|x86(_64)?|amd64|arm64|aarch64|'
+                         r'build|release|portable|steamos|v\d+([._]\d+)*|\d+([._]\d+)+))+$', re.I)
+
+
+def classify(path):
+    """{'format': 'elf'|'pe'|'script', 'arch', 'exe'} for an executable file, else None."""
+    try:
+        with open(path, 'rb') as f:
+            head = f.read(4096)
+            if head[:4] == b'\x7fELF':
+                return _elf(f, head)
+            if head[:2] == b'MZ':
+                return _pe(f, head)
+    except (OSError, struct.error, ValueError, OverflowError):
+        return None                        # unreadable, or a header that lies about its sizes
+    if head[:2] == b'#!' or path.lower().endswith('.sh'):
+        return {'format': 'script', 'arch': None, 'exe': True}
+    return None
+
+
+def _elf(f, head):
+    if len(head) < 64 or head[4] not in (1, 2) or head[5] not in (1, 2):
+        return None
+    wide, end = head[4] == 2, '<' if head[5] == 1 else '>'
+    e_type, machine = struct.unpack_from(end + 'HH', head, 16)
+    arch = ELF_MACHINES.get(machine, f'elf-0x{machine:x}')
+    if e_type == 2:                        # ET_EXEC
+        return {'format': 'elf', 'arch': arch, 'exe': True}
+    if e_type != 3:                        # not ET_DYN either: object file, core dump
+        return {'format': 'elf', 'arch': arch, 'exe': False}
+    # ET_DYN is a PIE executable or a shared library; only executables ask for an interpreter.
+    if wide:
+        phoff, = struct.unpack_from(end + 'Q', head, 32)
+        phentsize, phnum = struct.unpack_from(end + 'HH', head, 54)
+    else:
+        phoff, = struct.unpack_from(end + 'I', head, 28)
+        phentsize, phnum = struct.unpack_from(end + 'HH', head, 42)
+    if phentsize < (56 if wide else 32) or phnum > 256:
+        return {'format': 'elf', 'arch': arch, 'exe': False}
+    f.seek(phoff)
+    table = f.read(phentsize * phnum)
+    interp = any(struct.unpack_from(end + 'I', table, i * phentsize)[0] == 3   # PT_INTERP
+                 for i in range(len(table) // phentsize))
+    return {'format': 'elf', 'arch': arch, 'exe': interp}
+
+
+def _pe(f, head):
+    if len(head) < 0x40:
+        return None
+    lfanew, = struct.unpack_from('<I', head, 0x3C)
+    f.seek(lfanew)
+    coff = f.read(24)
+    if len(coff) < 24 or coff[:4] != b'PE\0\0':
+        return None                        # a DOS program, or not an executable at all
+    machine, = struct.unpack_from('<H', coff, 4)
+    characteristics, = struct.unpack_from('<H', coff, 22)
+    return {'format': 'pe', 'arch': PE_MACHINES.get(machine, f'pe-0x{machine:x}'),
+            'exe': not characteristics & 0x2000}   # IMAGE_FILE_DLL
+
+
+def title_id(name):
+    """The Devkit Game id Steam shows as the title's name: [A-Za-z0-9_-], at most 64."""
+    s = re.sub(r'[^A-Za-z0-9_-]+', '_', str(name or '').strip())
+    s = re.sub(r'_+', '_', s).strip('_-')[:64].strip('_-')
+    if not s:
+        raise FrameError('the title needs a name with some letters or digits')
+    if s.lower() in RESERVED_IDS:
+        s += '-game'
+    return s
+
+
+def display_name(filename):
+    """A title name from a zip, folder or exe name: no extension or build/platform words."""
+    base = os.path.basename(str(filename).rstrip('/\\'))
+    stem, ext = os.path.splitext(base)
+    if ext.lower() in ('.zip', '.exe', '.sh', '.x86_64', '.arm64', '.aarch64', '.bin'):
+        base = stem
+    return BUILD_WORDS.sub('', base) or base
+
+
+def _norm(s):
+    return re.sub(r'[^a-z0-9]', '', s.lower())
+
+
+# ---- payload: zip, folder or single file -> a local tree to upload ----------
+
+def extract_zip(zpath, dest):
+    """Unpack a zip into dest, refusing paths that escape it and absurd sizes."""
+    try:
+        z = zipfile.ZipFile(zpath)
+    except (zipfile.BadZipFile, OSError) as e:
+        raise FrameError(f'{os.path.basename(zpath)} is not a readable zip: {e}')
+    with z:
+        infos = z.infolist()
+        if len(infos) > MAX_ENTRIES:
+            raise FrameError(f'the zip has {len(infos)} entries; the limit is {MAX_ENTRIES}')
+        total = sum(i.file_size for i in infos)
+        packed = max(1, os.path.getsize(zpath))
+        if total > MAX_UNPACKED or (total > 1024**3 and total > packed * MAX_RATIO):
+            raise FrameError(f'the zip would unpack to {total / 1024**3:.1f} GB, which looks wrong')
+        free = shutil.disk_usage(dest).free
+        if total + 256 * 1024**2 > free:
+            raise FrameError(f'not enough space on this computer to unpack the zip '
+                             f'({total / 1024**3:.1f} GB needed, {free / 1024**3:.1f} GB free)')
+        try:
+            _extract_members(z, infos, os.path.realpath(dest))
+        except FrameError:
+            raise                            # a RuntimeError too, but already worded
+        except (zipfile.BadZipFile, RuntimeError, NotImplementedError, EOFError, OSError) as e:
+            # Encrypted or corrupt members, unsupported compression, clashing names, a full disk.
+            raise FrameError(f'could not unpack {os.path.basename(zpath)}: {e}')
+
+
+def _extract_members(z, infos, root):
+    # No symlink is ever created here, so no write can be redirected through one
+    # (chained links, Windows without the privilege). Links inside the zip are
+    # resolved on paper and materialised as copies once the real files are out.
+    links = {}
+    for info in infos:
+        rel = _safe_member(info.filename)
+        if rel is None:
+            continue
+        target = _inside(root, rel, info.filename)
+        mode = info.external_attr >> 16
+        if info.is_dir():
+            os.makedirs(target, exist_ok=True)
+            continue
+        os.makedirs(os.path.dirname(target), exist_ok=True)
+        if stat.S_ISLNK(mode):
+            if info.file_size > 4096:          # a link's content is a path, never this big
+                raise FrameError(f'the zip has an oversized link: {info.filename}')
+            link = z.read(info).decode('utf-8', 'replace').replace('\\', '/')
+            dest = posixpath.normpath(posixpath.join(posixpath.dirname(rel), link))
+            if link.startswith('/') or ':' in link or dest == '..' or dest.startswith('../'):
+                raise FrameError(f'the zip has a link that points outside it: {info.filename}')
+            links[rel] = link                  # as written: resolved later, one component at a time
+            continue
+        with z.open(info) as src, open(target, 'wb') as out:
+            shutil.copyfileobj(src, out, 1 << 20)
+        if mode & 0o111:
+            os.chmod(target, 0o755)
+    _materialise_links(root, links)
+
+
+def _inside(root, rel, name):
+    """rel's path under root, refusing anything that resolves outside it."""
+    target = os.path.join(root, *rel.split('/'))
+    if not (os.path.realpath(target) + os.sep).startswith(root + os.sep):
+        raise FrameError(f'the zip has a path that climbs out of it: {name}')
+    return target
+
+
+def _resolve_link(path, links):
+    """path with every link in it followed, on paper; None if it loops or leaves the zip.
+
+    Like the kernel: each component in turn, so 'dirlink/..' is the parent of
+    where dirlink points, not the folder dirlink sits in.
+    """
+    todo, done, hops = path.split('/'), [], 0
+    while todo:
+        part = todo.pop(0)
+        if part in ('', '.'):
+            continue
+        if part == '..':
+            if not done:
+                return None
+            done.pop()
+            continue
+        done.append(part)
+        text = links.get('/'.join(done))
+        if text is not None:
+            hops += 1
+            if hops > 40:
+                return None
+            done.pop()                        # link text is relative to the link's folder
+            todo = text.split('/') + todo
+    return '/'.join(done)
+
+
+def _materialise_links(root, links):
+    """Copy the file each link names into its place (lib.so.1 -> lib.so.1.2.3 and the like).
+
+    Only links to files: a folder link could hold itself, and game builds link
+    libraries, not folders. Folder, looping and dangling links are dropped.
+    """
+    copies = []
+    for rel in sorted(links):
+        dest = _resolve_link(rel, links)
+        if not dest:
+            continue                        # loops, escapes, or the zip's own top folder
+        src, target = _inside(root, dest, rel), _inside(root, rel, rel)
+        if os.path.isfile(src) and not os.path.lexists(target):   # a real entry may have the name
+            copies.append((src, target))
+    # Many links to one big file could fill the disk: the same limits as the zip itself.
+    need = sum(os.path.getsize(src) for src, _ in copies)
+    if need + _tree_size(root) > MAX_UNPACKED:
+        raise FrameError('the zip\'s links would copy more than it holds, which looks wrong')
+    if need + 256 * 1024**2 > shutil.disk_usage(root).free:
+        raise FrameError(f'not enough space on this computer for the zip\'s linked files ({need / 1024**3:.1f} GB)')
+    for src, target in copies:
+        os.makedirs(os.path.dirname(target), exist_ok=True)
+        shutil.copy2(src, target)
+
+
+def _safe_member(name):
+    """The member's relative path with / separators, None to skip it; raises if it escapes."""
+    rel = name.replace('\\', '/')
+    if rel.startswith('/') or re.match(r'^[A-Za-z]:', rel):
+        raise FrameError(f'the zip has an absolute path: {name}')
+    parts = [p for p in rel.split('/') if p not in ('', '.')]
+    if any(p == '..' for p in parts):
+        raise FrameError(f'the zip has a path that climbs out of it: {name}')
+    if any(':' in p for p in parts):
+        # Drive-qualified parts ('C:..') climb out on Windows; ':' is an NTFS stream elsewhere.
+        raise FrameError(f'the zip has a path with a drive or stream name: {name}')
+    if not parts or parts[0] == '__MACOSX' or parts[-1] in ('.DS_Store', 'Thumbs.db'):
+        return None
+    return '/'.join(parts)
+
+
+def _redirected(path, expected):
+    """True if path is a symlink, or resolves somewhere else (a Windows junction isn't islink)."""
+    return os.path.islink(path) or os.path.normcase(os.path.realpath(path)) != os.path.normcase(expected)
+
+
+def _has_links(root):
+    real = os.path.realpath(root)
+    for dirpath, dirnames, filenames in os.walk(real):
+        for n in dirnames + filenames:
+            if _redirected(os.path.join(dirpath, n), os.path.join(dirpath, n)):
+                return True
+    return False
+
+
+def _stage_folder(src, dest):
+    """Copy src to dest; links to files inside src become copies, all other links are left out."""
+    real = os.path.realpath(src)
+    inside = lambda p: os.path.normcase(p).startswith(os.path.normcase(real) + os.sep)  # noqa: E731
+    folders, copies = [], []                 # decide everything first, so the space check sees the same files
+    for dirpath, dirnames, filenames in os.walk(real):
+        out = os.path.join(dest, os.path.relpath(dirpath, real))
+        folders.append(out)
+        # Only descend into real folders: not symlinked ones, not junctions (os.walk follows those).
+        linked = [d for d in dirnames if _redirected(os.path.join(dirpath, d), os.path.join(dirpath, d))]
+        dirnames[:] = [d for d in dirnames if d not in linked]
+        for fn in filenames + linked:
+            target = os.path.realpath(os.path.join(dirpath, fn))
+            if inside(target) and os.path.isfile(target):
+                copies.append((target, os.path.join(out, fn)))
+    if shutil.disk_usage(os.path.dirname(dest)).free < sum(os.path.getsize(t) for t, _ in copies) + 256 * 1024**2:
+        raise FrameError('not enough space on this computer to stage the folder')
+    for out in folders:
+        os.makedirs(out, exist_ok=True)
+    for target, out in copies:
+        shutil.copy2(target, out)
+    return dest
+
+
+def _below(top, root):
+    """The folders _unwrap stepped through from top to root, as 'a/b', or ''. Taken
+    before staging moves root elsewhere (possibly another drive on Windows)."""
+    rel = os.path.relpath(root, os.path.realpath(top)).replace(os.sep, '/')
+    return '' if rel == '.' else rel
+
+
+def _unwrap(root):
+    """Step into a single top-level folder, the usual shape of a zipped build.
+
+    Never through a link or junction: the folder you chose (or unpacked) stays the boundary.
+    """
+    root = os.path.realpath(root)
+    for _ in range(4):
+        entries = [e for e in os.listdir(root) if e not in ('__MACOSX', '.DS_Store', 'Thumbs.db')]
+        if len(entries) != 1:
+            break
+        only = os.path.join(root, entries[0])
+        if not os.path.isdir(only) or _redirected(only, only):
+            break
+        root = only
+    return root
+
+
+def candidates(root, title=''):
+    """Executables under root, best launch target first."""
+    found = []
+    want = _norm(title)
+    for dirpath, dirnames, filenames in os.walk(root):
+        dirnames[:] = sorted(d for d in dirnames if not os.path.islink(os.path.join(dirpath, d)))
+        rel_dir = os.path.relpath(dirpath, root)
+        parts = [] if rel_dir == '.' else rel_dir.split(os.sep)
+        for fn in sorted(filenames):
+            full = os.path.join(dirpath, fn)
+            if os.path.islink(full) or not os.path.isfile(full):
+                continue
+            c = classify(full)
+            if not c or not c['exe']:
+                continue
+            stem = _norm(os.path.splitext(fn)[0])
+            skip = bool(SKIP_RE.search(fn)) or any(SKIP_DIRS.match(p) for p in parts)
+            match = 2 if want and stem == want else 1 if want and stem and (want in stem or stem in want) else 0
+            found.append({'path': '/'.join(parts + [fn]), 'format': c['format'], 'arch': c['arch'],
+                          'size': os.path.getsize(full), 'depth': len(parts), 'skip': skip, 'match': match})
+    found.sort(key=_rank)
+    _prefer_launcher_script(found)
+    return found
+
+
+def _platform_rank(c):
+    # Native ARM64 first, then Proton, then x86-64 Linux through FEX; scripts are placed separately.
+    order = {('elf', 'arm64'): 0, ('pe', 'x86_64'): 1, ('elf', 'x86_64'): 2, ('pe', 'x86'): 3, ('pe', 'arm64'): 3}
+    return order.get((c['format'], c['arch']), 5 if c['format'] == 'script' else 6)
+
+
+def _rank(c):
+    return (c['skip'], _platform_rank(c), -c['match'], c['depth'], -c['size'], c['path'])
+
+
+def _prefer_launcher_script(found):
+    """A top-level shell script beats a Linux binary one folder down (run.sh + bin/game)."""
+    if not found or found[0]['format'] != 'elf' or found[0]['depth'] == 0:
+        return
+    for i, c in enumerate(found):
+        if c['format'] == 'script' and c['depth'] == 0 and not c['skip']:
+            found.insert(0, found.pop(i))
+            return
+
+
+def runtime_for(target, found=()):
+    """(compat tool alias, note) for a launch target, or raise FrameError if it can't run."""
+    fmt, arch = target['format'], target['arch']
+    if fmt == 'script':
+        # A script runs in the runtime of the binaries next to it; alone, natively.
+        elf = next((c for c in found if c['format'] == 'elf' and not c['skip']), None)
+        if elf:
+            return runtime_for(elf)[0], 'A shell script; runtime chosen from the Linux binary next to it.'
+        return 'SteamLinuxRuntime_4-arm64', 'A shell script with no Linux binary beside it; run natively.'
+    if fmt == 'pe':
+        if arch not in ('x86_64', 'x86', 'arm64'):
+            raise FrameError(f"{target['path']} is a Windows program for {arch}, which Proton can't run")
+        note = 'Windows x86-64 build: Proton runs it through FEX.' if arch == 'x86_64' else \
+            f'Windows {arch} build under Proton.'
+        return DEFAULT_PROTON, note
+    if fmt == 'elf' and arch == 'arm64':
+        return 'SteamLinuxRuntime_4-arm64', 'Native ARM64 Linux build.'
+    if fmt == 'elf' and arch == 'x86_64':
+        return 'SteamLinuxRuntime_4', ("x86-64 Linux build: probably won't start. It needs the x86-64 Steam "
+                                       "Linux Runtime 4.0, which the Frame didn't install for a sideloaded title "
+                                       "(2026-09-26). Use an ARM64 or Windows build if there is one.")
+    raise FrameError(f"{target['path']} is a {arch} Linux program; the Frame runs ARM64 and x86-64 (through FEX) only")
+
+
+def allowed_runtimes(target, found=()):
+    alias, _ = runtime_for(target, found)
+    return ['proton-experimental', 'proton-stable'] if RUNTIMES[alias]['steam_play'] else [alias]
+
+
+def inspect(path, name=None):
+    """Read a .zip, folder or executable into an install plan (a JSON-safe dict).
+
+    A zip is unpacked into a temporary folder, plan['work']; pass the plan to
+    discard() when done with it. Raises FrameError if nothing in it can run.
+    """
+    path = os.path.abspath(path)
+    if not os.path.exists(path):
+        raise FrameError(f'{path} does not exist')
+    work = None
+    try:
+        if os.path.isdir(path):
+            root = _unwrap(path)
+            unwrapped = _below(path, root)
+            if _has_links(root):
+                # scp -r follows links, so a link out of the folder could upload
+                # anything; copy the folder with its links made safe first.
+                work = tempfile.mkdtemp(prefix=f'{TMP_PREFIX}{os.getpid()}-')
+                root = _stage_folder(root, os.path.join(work, os.path.basename(root)))
+        elif path.lower().endswith('.zip'):
+            work = tempfile.mkdtemp(prefix=f'{TMP_PREFIX}{os.getpid()}-')
+            extract_zip(path, work)
+            root = _unwrap(work)
+            unwrapped = _below(work, root)
+        elif classify(path):
+            # A single executable is uploaded on its own; don't copy a whole Downloads folder.
+            work = tempfile.mkdtemp(prefix=f'{TMP_PREFIX}{os.getpid()}-')
+            shutil.copy2(path, os.path.join(work, os.path.basename(path)))
+            root, unwrapped = work, ''
+        else:
+            raise FrameError(f'{os.path.basename(path)} is not a .zip, a folder or a program')
+        title = name or display_name(os.path.basename(path.rstrip('/\\')))
+        found = candidates(root, title)
+        if not found:
+            raise FrameError(f'no Linux or Windows program found in {os.path.basename(path)}')
+        plan = {'source': os.path.basename(path.rstrip('/\\')), 'name': title, 'id': title_id(title),
+                'root': root, 'work': work, 'candidates': found,
+                'unwrapped': unwrapped,
+                'size': _tree_size(root), 'warnings': []}
+        _choose(plan, found[0]['path'])
+        return plan
+    except BaseException:
+        if work:
+            shutil.rmtree(work, ignore_errors=True)
+        raise
+
+
+def _tree_size(root):
+    total = 0
+    for dirpath, _, filenames in os.walk(root):
+        for fn in filenames:
+            full = os.path.join(dirpath, fn)
+            if os.path.isfile(full) and not os.path.islink(full):
+                total += os.path.getsize(full)
+    return total
+
+
+def _choose(plan, rel, runtime=None):
+    """Set plan's launch target (a path relative to root) and its runtime."""
+    rel = rel.replace('\\', '/')
+    # A manifest may name the program as it is in the archive, above the folder
+    # _unwrap stepped into. A path that works as it is always wins.
+    prefix = plan.get('unwrapped') and plan['unwrapped'] + '/'
+    if (prefix and rel.startswith(prefix) and not any(c['path'] == rel for c in plan['candidates'])
+            and not os.path.isfile(os.path.join(plan['root'], *rel.split('/')))):
+        rel = rel[len(prefix):]
+    target = next((c for c in plan['candidates'] if c['path'] == rel), None)
+    if target is None:
+        full = os.path.realpath(os.path.join(plan['root'], *rel.replace('\\', '/').split('/')))
+        root = os.path.realpath(plan['root'])
+        if not (full + os.sep).startswith(root + os.sep) or not os.path.isfile(full):
+            raise FrameError(f'{rel} is not a file in the title')
+        c = classify(full)
+        if not c or not c['exe']:
+            raise FrameError(f"{rel} isn't a program the Frame can start")
+        target = {'path': os.path.relpath(full, root).replace(os.sep, '/'), 'format': c['format'],
+                  'arch': c['arch'], 'size': os.path.getsize(full), 'depth': rel.count('/'),
+                  'skip': False, 'match': 0}
+    alias, note = runtime_for(target, plan['candidates'])
+    allowed = allowed_runtimes(target, plan['candidates'])
+    if runtime:
+        if runtime not in allowed:
+            raise FrameError(f"{target['path']} can't use {runtime}; choose one of {', '.join(allowed)}")
+        alias = runtime
+    plan.update(target=target['path'], format=target['format'], arch=target['arch'], runtime=alias,
+                runtime_label=RUNTIMES[alias]['label'], runtimes=allowed, note=note)
+    plan['warnings'] = (['This looks like an installer or helper, not the game itself.'] if target['skip'] else [])
+    return plan
+
+
+def discard(plan):
+    if plan and plan.get('work'):
+        shutil.rmtree(plan['work'], ignore_errors=True)
+
+
+def argv_for(rel):
+    # Valve's client sends the start command as one string (it may carry arguments),
+    # so a path with spaces is quoted. How Steam splits it is inferred.
+    return ['"' + rel + '"' if re.search(r'\s', rel) else rel]
+
+
+def shortcut_parms(gameid, directory, rel, runtime):
+    """The JSON steam-client-create-shortcut takes, as devkit_client.new_or_ensure_game builds it."""
+    settings = {'steam_play': '1' if RUNTIMES[runtime]['steam_play'] else '0'}
+    if RUNTIMES[runtime]['steam_play']:
+        # gui2._update_game sends these with every Proton title; debugging stays off.
+        settings.update(steam_play_debug='0', steam_play_debug_version='2019')
+    settings['compat_tool'] = runtime
+    return {'gameid': gameid, 'directory': directory, 'argv': argv_for(rel), 'env': {},
+            'settings': settings, 'clear_settings': True, 'force_appid': '', 'lepton_args': ''}
+
+
+# ---- the Frame side ----------------------------------------------------------
+
+def ssh(cmd, input=None, timeout=120):
+    return frame_android.ssh(cmd, input=input, timeout=timeout)
+
+
+def _json_out(out, what):
+    """The JSON object a devkit-utils script prints last (its logging goes to stderr)."""
+    for line in reversed(out.strip().splitlines()):
+        line = line.strip()
+        if line.startswith('{') or line.startswith('['):
+            try:
+                return json.loads(line)
+            except ValueError:
+                break
+    raise FrameError(f'{what} gave no usable answer: {out.strip()[-300:]!r}')
+
+
+def utils_stamp():
+    """Hash of the vendored devkit-utils, compared with the copy on the Frame."""
+    h = hashlib.sha256()
+    for dirpath, dirnames, filenames in os.walk(UTILS_LOCAL):
+        dirnames[:] = sorted(d for d in dirnames if d != '__pycache__')
+        for fn in sorted(filenames):
+            if fn.endswith('.pyc'):
+                continue
+            full = os.path.join(dirpath, fn)
+            h.update(os.path.relpath(full, UTILS_LOCAL).replace(os.sep, '/').encode() + b'\0')
+            with open(full, 'rb') as f:
+                h.update(f.read())
+    return h.hexdigest()[:20]
+
+
+def _json_files(gid):
+    # Exact names: a glob like Game-*.json would also match another title called Game-Deluxe.
+    return ' '.join(f'{GAMES}/{gid}-{k}.json' for k in ('argv', 'env', 'settings', 'framecontrol'))
+
+
+_utils_lock = threading.Lock()
+
+
+def ensure_utils():
+    """Copy frame/devkit-utils to ~/devkit-utils on the Frame unless it's already this version."""
+    with _utils_lock:                        # one sync at a time: they share a staging folder
+        return _ensure_utils()
+
+
+def _ensure_utils():
+    stamp = utils_stamp()
+    have = ssh(f'cat {UTILS}/{STAMP} 2>/dev/null || true', timeout=30).strip()
+    if have == stamp:
+        return False
+    # Merge rather than replace: Valve's own client may have put newer files there.
+    tmp = f'.{UTILS}.frame-control'
+    ssh(f'rm -rf {tmp}', timeout=30)
+    _copy_tree(UTILS_LOCAL, tmp, timeout=300)
+    ssh(f'mkdir -p {UTILS} && cp -R {tmp}/. {UTILS}/ && rm -rf {tmp} {UTILS}/__pycache__ '
+        f'&& echo {stamp} > {UTILS}/{STAMP}', timeout=60)
+    return True
+
+
+def _copy_tree(src, dest, timeout=3 * 3600, delete=False):
+    """Copy a local folder's contents to dest on the Frame (dest ends up a copy of src).
+
+    rsync where installed (not on Windows; see server.push_file), else scp -r
+    into a fresh dest, which is what Windows has. dest must be a plain path.
+    """
+    name = os.path.basename(src.rstrip('/\\'))
+    opts = frame_android.SSH_OPTS           # read now: the server swaps in its multiplexed options
+    if _rsync():
+        cmd = ['rsync', '-a', *(['--delete'] if delete else []), '-e', shlex.join(['ssh', *opts]),
+               src.rstrip('/') + '/', f'{frame_android.FRAME}:{dest.rstrip("/")}/']
+    else:
+        # scp -r copies src *into* dest when dest exists, so dest must not.
+        ssh(f'rm -rf {shlex.quote(dest)}', timeout=60)
+        cmd = ['scp', *opts, '-r', src, f'{frame_android.FRAME}:{dest}']
+    try:
+        subprocess.run(cmd, check=True, capture_output=True, stdin=subprocess.DEVNULL, text=True,
+                       errors='replace', timeout=timeout)
+    except subprocess.TimeoutExpired:
+        raise FrameError(f'copying {name} to the Frame timed out')
+    except subprocess.CalledProcessError as e:
+        raise FrameError(f'copying {name} to the Frame failed: {(e.stderr or "").strip()[-300:]}')
+
+
+def _rsync():
+    # Not on Windows: a Windows rsync (cwRsync, MSYS2) wouldn't take the POSIX -e quoting.
+    return not frame_host.WINDOWS and bool(shutil.which('rsync'))
+
+
+_install_lock = threading.Lock()
+
+
+def install(path, name=None, exe=None, runtime=None, progress=None):
+    """Sideload a .zip, folder or executable as a Devkit Game; returns the title dict.
+
+    name: the Steam name (sanitised to the title id), default from the file name.
+    exe: launch target relative to the title's root, default the best candidate.
+    runtime: a compat tool alias from RUNTIMES that suits the target (e.g.
+    'proton-stable' instead of the default Proton Experimental).
+    progress: optional callable(stage_text, fraction 0..1).
+    """
+    plan = inspect(path, name)
+    try:
+        return install_plan(plan, name=name, exe=exe, runtime=runtime, progress=progress)
+    finally:
+        discard(plan)
+
+
+def install_plan(plan, name=None, exe=None, runtime=None, progress=None):
+    """Install an inspect() plan, optionally with another name, target or runtime."""
+    if name:
+        plan['name'], plan['id'] = name, title_id(name)
+    if exe or runtime:
+        _choose(plan, exe or plan['target'], runtime)
+    step = progress or (lambda *a: None)
+    with _install_lock:
+        return _install(plan, step)
+
+
+def _install(plan, step):
+    gid = plan['id']
+    if not ID_RE.match(gid) or gid.lower() in RESERVED_IDS:
+        raise FrameError(f'bad title id {gid!r}')
+    step("Syncing Valve's devkit tools to the Frame", 0.02)
+    ensure_utils()
+    existed = ssh(f'test -d {GAMES}/{gid} && echo yes || true', timeout=30).strip() == 'yes'
+    step('Preparing the title folder', 0.05)
+    ready = _json_out(ssh(f'{PY}steamos-prepare-upload --gameid {gid}', timeout=60), 'steamos-prepare-upload')
+    directory = str(ready.get('directory') or '')
+    if not DIR_RE.match(directory) or not directory.endswith(f'/{GAMES}/{gid}'):
+        raise FrameError(f'steamos-prepare-upload returned an unexpected folder {directory!r}')
+    registered = False
+    try:
+        step(f"Copying {plan['size'] / 1e6:.0f} MB to the Frame", 0.1)
+        if _rsync():
+            _copy_tree(plan['root'], directory, delete=True)
+        else:
+            part = f"{directory.rsplit('/', 1)[0]}/.{gid}.upload"
+            _copy_tree(plan['root'], part)
+            ssh(f'rm -rf {directory} && mv {part} {directory}', timeout=120)
+        # Same modes Valve's client gives an upload (rsync --chmod=Du=rwx,Dgo=rx,Fu=rwx,Fog=rx).
+        ssh(f'chmod -R 755 {directory}', timeout=300)
+        step('Registering with Steam', 0.9)
+        parms = shortcut_parms(gid, directory, plan['target'], plan['runtime'])
+        reply = _json_out(ssh(f'{PY}steam-client-create-shortcut --parms {shlex.quote(json.dumps(parms))}',
+                              timeout=90), 'steam-client-create-shortcut')
+        meta = {'id': gid, 'name': plan['name'], 'target': plan['target'], 'runtime': plan['runtime'],
+                'source': plan['source'], 'size': plan['size'], 'installed': time.strftime('%Y-%m-%dT%H:%M:%S')}
+        ssh(f'cat > {GAMES}/{gid}-framecontrol.json', input=json.dumps(meta, indent=1), timeout=30)
+        registered = True                    # the files stay: Steam registers them once it's running
+        if 'error' in reply:
+            raise FrameError(f"Uploaded, but Steam didn't register it: {reply['error']}. "
+                             "With Steam running on the Frame, install it again.")
+        step('Done', 1.0)
+        meta.update(runtime_label=RUNTIMES[plan['runtime']]['label'], steam=str(reply.get('success', '')).strip())
+        return meta
+    finally:
+        if not registered and not existed:
+            # A first install that failed part-way: don't leave an orphan folder behind.
+            try:
+                ssh(f'rm -rf {GAMES}/{gid} {GAMES}/.{gid}.upload {_json_files(gid)}', timeout=60)
+            except FrameError:
+                pass
+
+
+LIST_SCRIPT = r'''
+import json, os
+root = os.path.expanduser('~/devkit-game')
+reserved = %r
+out = []
+for d in sorted(os.listdir(root)) if os.path.isdir(root) else []:
+    if d.startswith('.') or d.lower() in reserved or not os.path.isdir(os.path.join(root, d)):
+        continue
+    t = {'id': d}
+    for key, suffix in (('settings', '-settings.json'), ('argv', '-argv.json'), ('meta', '-framecontrol.json')):
+        try:
+            with open(os.path.join(root, d + suffix)) as f:
+                t[key] = json.load(f)
+        except (OSError, ValueError):
+            t[key] = None
+    out.append(t)
+print(json.dumps(out))
+''' % (RESERVED_IDS,)
+
+
+def list_titles():
+    """The Devkit Games on the Frame (any uploaded by Valve's client too)."""
+    raw = _json_out(ssh('python3 -', input=LIST_SCRIPT, timeout=30), 'the title list')
+    titles = []
+    for t in raw if isinstance(raw, list) else []:
+        if not ID_RE.match(str(t.get('id', ''))):
+            continue
+        settings, meta = t.get('settings') or {}, t.get('meta') or {}
+        argv = t.get('argv') if isinstance(t.get('argv'), list) else []
+        alias = str(settings.get('compat_tool') or '')
+        titles.append({'id': t['id'], 'name': str(meta.get('name') or t['id']),
+                       'target': str(meta.get('target') or (argv[0] if argv else '')),
+                       'runtime': alias, 'runtime_label': RUNTIMES.get(alias, {}).get('label', alias or 'not set'),
+                       'source': str(meta.get('source') or ''), 'size': meta.get('size'),
+                       'installed': meta.get('installed'), 'registered': t.get('settings') is not None,
+                       'frame_control': bool(meta)})
+    return titles
+
+
+def _check_id(gid):
+    gid = str(gid or '')
+    if not ID_RE.match(gid) or gid.lower() in RESERVED_IDS:
+        raise FrameError(f'bad title id {gid!r}')
+    if ssh(f'test -d {GAMES}/{gid} && echo yes || true', timeout=30).strip() != 'yes':
+        raise FrameError(f'{gid} is not installed')
+    return gid
+
+
+def launch(gid):
+    gid = _check_id(gid)
+    ensure_utils()
+    # steam-devkit-rpc logs 'success' when Steam answers, but exits 0 after a
+    # 5 s timeout too, so read its log (stderr) rather than trust the exit code.
+    out = ssh(f'{PY}steam-devkit-rpc run-game gameid={gid} 2>&1', timeout=60)
+    if 'success' not in [line.strip() for line in out.splitlines()]:
+        raise FrameError(f"Steam didn't confirm the launch: {out.strip()[-300:] or 'no answer'}")
+    return {'id': gid}
+
+
+def remove(gid):
+    # Not while an install runs: it could be this title, half copied or about to register.
+    if not _install_lock.acquire(blocking=False):
+        raise FrameError('an install is running; remove the title when it has finished')
+    try:
+        gid = _check_id(gid)
+        ensure_utils()
+        # steamos-delete removes the folder and syncs Steam's shortcuts; its json files stay, so clear them too.
+        ssh(f'{PY}steamos-delete --delete-title {gid}', timeout=120)
+        ssh(f'rm -f {_json_files(gid)}', timeout=30)
+        return {'id': gid}
+    finally:
+        _install_lock.release()
+
+
+def public(plan):
+    """A plan without its local paths, for the UI, with the runtimes each candidate may use."""
+    out = {k: v for k, v in plan.items() if k not in ('root', 'work', 'candidates')}
+    out['candidates'] = []
+    for c in plan['candidates']:
+        c = dict(c)
+        try:
+            c['runtimes'] = allowed_runtimes(c, plan['candidates'])
+        except FrameError as e:
+            c['runtimes'], c['blocked'] = [], str(e)
+        out['candidates'].append(c)
+    out['runtime_labels'] = {k: v['label'] for k, v in RUNTIMES.items()}
+    return out
+
+
+def main():
+    cmd, *args = sys.argv[1:] or ['help']
+
+    def opt(flag):
+        return args[args.index(flag) + 1] if flag in args and args.index(flag) + 1 < len(args) else None
+
+    try:
+        if cmd == 'inspect' and args:
+            plan = inspect(args[0], opt('--name'))
+            try:
+                if opt('--exe') or opt('--runtime'):
+                    _choose(plan, opt('--exe') or plan['target'], opt('--runtime'))
+                r = public(plan)
+            finally:
+                discard(plan)
+        elif cmd == 'install' and args:
+            r = install(args[0], name=opt('--name'), exe=opt('--exe'), runtime=opt('--runtime'),
+                        progress=lambda text, _: print(text + '…', file=sys.stderr))
+        elif cmd == 'list':
+            r = list_titles()
+        elif cmd in ('launch', 'remove') and args:
+            r = globals()[cmd](args[0])
+        else:
+            sys.exit(__doc__)
+    except FrameError as e:
+        sys.exit(f'error: {e}')
+    print(json.dumps(r, indent=1))
+
+
+if __name__ == '__main__':
+    main()
diff --git a/ui/frame_webinstall.py b/ui/frame_webinstall.py
new file mode 100644
index 0000000..2f2e006
--- /dev/null
+++ b/ui/frame_webinstall.py
@@ -0,0 +1,468 @@
+"""Install links from websites: frame-control://install?manifest=URL or ?url=URL.
+
+The app hands the link to the page, the page shows what it will install and
+asks the user first, and only then does this module download the file and pass
+it to the installer for its type (dispatch()). See docs/web-install.md.
+
+A manifest is the same JSON FrameDrop uses, so one works for both tools:
+    {"schema": "framedrop.install/v1", "name": "My Game",
+     "files": [{"url": "https://cdn.example.com/mygame-arm64.apk", "sha256": "..."}]}
+"frame-control.install/v1" is accepted with the same shape.
+
+Rules: HTTPS only, except http(s)://localhost or 127.0.0.1 for testing, and then
+only with FRAME_CONTROL_LOCAL_LINKS=1 set and when the link itself points there.
+No credentials in URLs, no private, loopback, link-local or CGNAT addresses
+(checked on every redirect, and the connection goes to the address that was
+checked, so DNS can't change it in between). The file URL must end in a file name.
+
+Python stdlib only, 3.9 compatible.
+"""
+import hashlib
+import http.client
+import ipaddress
+import json
+import os
+import errno
+import re
+import select
+import socket
+import ssl
+import tempfile
+import time
+from urllib.parse import unquote, urljoin, urlsplit
+
+SCHEMAS = ("framedrop.install/v1", "frame-control.install/v1")
+MAX_FILE = 4 * 1024**3        # largest download accepted
+MAX_MANIFEST = 256 * 1024     # largest manifest accepted
+MAX_URL = 2048
+MAX_REDIRECTS = 5
+TIMEOUT = 30                  # seconds per socket operation
+CHUNK = 1 << 20
+LOCAL_HOSTS = ("localhost", "127.0.0.1")
+# Off by default: otherwise any website could make the app fetch from local services.
+LOCAL_LINKS_ENV = "FRAME_CONTROL_LOCAL_LINKS"
+USER_AGENT = "FrameControl (+https://github.com/saphid/steam-frame)"
+# What dispatch() can install, by file extension.
+KINDS = {".apk": "apk", ".zip": "title", ".exe": "title"}
+KIND_LABEL = {"apk": "Android app (APK)", "title": "Linux/Windows title"}
+SHA256 = re.compile(r"[0-9a-fA-F]{64}")
+CGNAT = ipaddress.ip_network("100.64.0.0/10")
+# connect_ex() results meaning "still connecting" (the last is Windows' WSAEWOULDBLOCK).
+_CONNECTING = {errno.EINPROGRESS, errno.EWOULDBLOCK, errno.EALREADY, getattr(errno, "WSAEWOULDBLOCK", 10035)}
+
+# Swapped out by the tests, which have no network.
+_getaddrinfo = socket.getaddrinfo
+
+
+class WebInstallError(Exception):
+    pass
+
+
+class Cancelled(WebInstallError):
+    pass
+
+
+# ---- URLs -------------------------------------------------------------------
+
+def is_public(ip):
+    """True for addresses on the public internet, and nothing a LAN or this computer uses."""
+    ip = ipaddress.ip_address(ip)
+    if ip.version == 6:
+        if ip.ipv4_mapped:
+            ip = ip.ipv4_mapped
+        elif ip.is_site_local:  # fec0::/10: deprecated, but is_global doesn't catch it
+            return False
+        elif ip.sixtofour and not is_public(ip.sixtofour):
+            return False
+    if ip.version == 4 and ip in CGNAT:
+        return False
+    return ip.is_global and not ip.is_multicast
+
+
+def check_url(url, allow_local=False):
+    """Validate a URL against the rules above; returns (scheme, host, port, is_local).
+
+    Resolving the name is left to connect time (see _resolve), so this needs no network.
+    """
+    if not isinstance(url, str) or not url or len(url) > MAX_URL:
+        raise WebInstallError("the link must be a URL of at most %d characters" % MAX_URL)
+    if any(c.isspace() or ord(c) < 32 for c in url):
+        raise WebInstallError("the URL has spaces or control characters in it")
+    try:
+        u = urlsplit(url)
+        port = u.port
+    except ValueError as e:
+        raise WebInstallError(f"not a valid URL: {e}")
+    scheme = u.scheme.lower()
+    if scheme not in ("https", "http"):
+        raise WebInstallError(f"only https:// links are allowed, not {scheme or 'a relative URL'}")
+    if u.username is not None or u.password is not None or "@" in u.netloc:
+        raise WebInstallError("URLs with a user name or password in them aren't allowed")
+    host = (u.hostname or "").lower().rstrip(".")
+    if not host:
+        raise WebInstallError("the URL has no host")
+    local = host in LOCAL_HOSTS
+    if local and not allow_local:
+        raise WebInstallError(f"localhost links are for testing: set {LOCAL_LINKS_ENV}=1, and the link itself must point there")
+    if scheme == "http" and not local:
+        raise WebInstallError("only https:// is allowed (http:// only for localhost while testing)")
+    if not local:
+        try:
+            literal = ipaddress.ip_address(host)
+        except ValueError:
+            literal = None
+        if literal is not None and not is_public(literal):
+            raise WebInstallError(f"{host} is a private or local address")
+    return scheme, host, port or (443 if scheme == "https" else 80), local
+
+
+def file_name(url):
+    """The file name the URL ends in, e.g. mygame-arm64.apk."""
+    path = urlsplit(url).path
+    name = unquote(path.rsplit("/", 1)[-1])
+    if not name or name in (".", "..") or "/" in name or "\\" in name or name.startswith(".") \
+            or any(ord(c) < 32 for c in name) or len(name) > 200:
+        raise WebInstallError("the file URL must end in a file name, e.g. https://example.com/mygame.apk")
+    return name
+
+
+def file_kind(name):
+    ext = os.path.splitext(name.lower())[1]
+    kind = KINDS.get(ext)
+    if not kind:
+        raise WebInstallError(f"{name}: Frame Control installs .apk, .zip and .exe files, not {ext or 'this type'}")
+    return kind
+
+
+def _resolve(host, port, local):
+    """One address to connect to; every address the name has must be public."""
+    if local:
+        return "127.0.0.1"
+    try:
+        infos = _getaddrinfo(host, port, type=socket.SOCK_STREAM)
+    except (OSError, UnicodeError) as e:
+        raise WebInstallError(f"couldn't look up {host}: {e}")
+    ips = [info[4][0].split("%", 1)[0] for info in infos]
+    if not ips:
+        raise WebInstallError(f"couldn't look up {host}")
+    for ip in ips:
+        if not is_public(ip):
+            raise WebInstallError(f"{host} points to a private or local address ({ip})")
+    return ips[0]
+
+
+# ---- HTTP -------------------------------------------------------------------
+
+class _Abortable:
+    """Connects to an address checked beforehand, whatever DNS says by then.
+
+    raw_sock is the socket to shut down to stop the connection from another
+    thread (abort()): http.client drops conn.sock once a response will close
+    the connection, yet keeps reading the body from it.
+    """
+    raw_sock = None
+    aborted = False
+
+    def _tcp(self):
+        """Connect without blocking, so abort() can stop a connect that hangs."""
+        sock = socket.socket(socket.AF_INET6 if ":" in self._ip else socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            sock.setblocking(False)
+            err = sock.connect_ex((self._ip, self.port))
+            deadline = time.monotonic() + self.timeout
+            while err in _CONNECTING:
+                if self.aborted:
+                    raise OSError("aborted")
+                if time.monotonic() > deadline:
+                    raise socket.timeout(f"timed out connecting to {self.host}")
+                _, writable, failed = select.select([], [sock], [sock], 0.2)
+                if writable or failed:
+                    err = sock.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
+            if err:
+                raise OSError(err, os.strerror(err))
+            sock.settimeout(self.timeout)
+            self.raw_sock = sock
+            if self.aborted:  # abort() ran just now and found nothing to shut down
+                raise OSError("aborted")
+        except BaseException:
+            sock.close()
+            raise
+        return sock
+
+
+class _HTTPConnection(_Abortable, http.client.HTTPConnection):
+    def __init__(self, host, ip, port, timeout):
+        super().__init__(host, port, timeout=timeout)
+        self._ip = ip
+
+    def connect(self):
+        self.sock = self._tcp()
+
+
+class _HTTPSConnection(_Abortable, http.client.HTTPSConnection):
+    """As above, still verifying the certificate for the host name."""
+
+    def __init__(self, host, ip, port, timeout):
+        # urllib's default context, so the app's bundled CA list (frame_host.trust_bundled_cas) applies too.
+        super().__init__(host, port, timeout=timeout, context=ssl._create_default_https_context())
+        self._ip = ip
+
+    def connect(self):
+        # Wrapping detaches the plain socket, so publish the TLS one before the handshake.
+        sock = self._context.wrap_socket(self._tcp(), server_hostname=self.host, do_handshake_on_connect=False)
+        self.raw_sock = sock
+        try:
+            if self.aborted:
+                raise OSError("aborted")
+            sock.do_handshake()
+        except (AttributeError, ValueError) as e:
+            # abort()'s shutdown() can tear down the TLS state mid-way.
+            sock.close()
+            if self.aborted:
+                raise OSError("aborted")
+            raise OSError(str(e))
+        except BaseException:
+            sock.close()
+            raise
+        self.sock = sock
+
+
+def _open(url, allow_local, method="GET", connected=None):
+    """(connection, response) for url after redirects, each hop checked. Caller closes the connection.
+
+    connected(conn) gets each connection before it's used, for abort().
+    """
+    for _ in range(MAX_REDIRECTS + 1):
+        scheme, host, port, local = check_url(url, allow_local)
+        ip = _resolve(host, port, local)
+        cls = _HTTPSConnection if scheme == "https" else _HTTPConnection
+        conn = cls(host, ip, port, TIMEOUT)
+        if connected:
+            connected(conn)
+        u = urlsplit(url)
+        target = (u.path or "/") + ("?" + u.query if u.query else "")
+        try:
+            conn.request(method, target, headers={"User-Agent": USER_AGENT, "Accept-Encoding": "identity"})
+            r = conn.getresponse()
+        except (OSError, http.client.HTTPException) as e:
+            conn.close()
+            raise WebInstallError(f"couldn't reach {host}: {e}")
+        if r.status in (301, 302, 303, 307, 308) and r.getheader("Location"):
+            url = urljoin(url, r.getheader("Location").strip())
+            conn.close()
+            continue
+        if r.status != 200:
+            conn.close()
+            raise WebInstallError(f"{host} answered HTTP {r.status} {r.reason}".strip())
+        return conn, r
+    raise WebInstallError(f"more than {MAX_REDIRECTS} redirects")
+
+
+def _length(r):
+    try:
+        n = int(r.getheader("Content-Length") or "")
+    except ValueError:
+        return None
+    return n if n >= 0 else None
+
+
+# ---- manifests --------------------------------------------------------------
+
+def parse_manifest(obj):
+    """{"name": ..., "file": {"url", "sha256", "size", "exe"}} from a manifest object."""
+    if not isinstance(obj, dict):
+        raise WebInstallError("the manifest must be a JSON object")
+    schema = obj.get("schema")
+    if schema not in SCHEMAS:
+        raise WebInstallError(f"unsupported manifest schema {schema!r} (expected {' or '.join(SCHEMAS)})")
+    files = obj.get("files")
+    if not isinstance(files, list) or not files:
+        raise WebInstallError("the manifest has no files")
+    if len(files) > 1:
+        raise WebInstallError(f"the manifest lists {len(files)} files; Frame Control installs one file per link for now")
+    entry = files[0]
+    if not isinstance(entry, dict) or not isinstance(entry.get("url"), str) or not entry["url"]:
+        raise WebInstallError("the manifest's file has no url")
+    sha = entry.get("sha256")
+    if sha is not None and (not isinstance(sha, str) or not SHA256.fullmatch(sha)):
+        raise WebInstallError("sha256 must be 64 hex digits")
+    size = entry.get("size")
+    if size is not None and (type(size) is not int or size <= 0):
+        raise WebInstallError("size must be a positive integer")
+    exe = entry.get("exe")
+    if exe is not None and (not isinstance(exe, str) or not exe or len(exe) > 300):
+        raise WebInstallError("exe must be a path inside the archive")
+    name = obj.get("name")
+    if name is not None and not isinstance(name, str):
+        raise WebInstallError("name must be a string")
+    return {"name": clean_name(name), "file": {"url": entry["url"], "sha256": sha.lower() if sha else None,
+                                               "size": size, "exe": exe}}
+
+
+def clean_name(name):
+    name = re.sub(r"[\x00-\x1f\x7f]", "", name or "").strip()
+    return name[:120] or None
+
+
+def fetch_manifest(url, allow_local):
+    conn, r = _open(url, allow_local)
+    try:
+        n = _length(r)
+        if n is not None and n > MAX_MANIFEST:
+            raise WebInstallError(f"the manifest is over {MAX_MANIFEST // 1024} KB")
+        data = r.read(MAX_MANIFEST + 1)
+    except (OSError, http.client.HTTPException) as e:
+        raise WebInstallError(f"couldn't read the manifest: {e}")
+    finally:
+        conn.close()
+    if len(data) > MAX_MANIFEST:
+        raise WebInstallError(f"the manifest is over {MAX_MANIFEST // 1024} KB")
+    try:
+        obj = json.loads(data.decode("utf-8"))
+    except (UnicodeDecodeError, ValueError):
+        raise WebInstallError("the manifest isn't valid JSON")
+    return parse_manifest(obj)
+
+
+def _head_size(url, allow_local):
+    """Content-Length from a HEAD request, or None; only for showing the size up front."""
+    try:
+        conn, r = _open(url, allow_local, method="HEAD")
+    except WebInstallError:
+        return None
+    try:
+        return _length(r)
+    finally:
+        conn.close()
+
+
+def plan(manifest=None, url=None):
+    """Everything the confirm dialog shows, fetched and checked; nothing is downloaded yet.
+
+    Exactly one of manifest (a manifest URL) or url (a direct file URL).
+    """
+    if (manifest is None) == (url is None):
+        raise WebInstallError("give either manifest or url")
+    link = manifest if manifest is not None else url
+    # localhost is for testing a link on your own computer: only with the developer
+    # switch on, and only for a link that starts there (a public manifest can't
+    # point at localhost).
+    allow_local = check_url(link, allow_local=os.environ.get(LOCAL_LINKS_ENV) == "1")[3]
+    if manifest is not None:
+        m = fetch_manifest(manifest, allow_local)
+        name, f = m["name"], m["file"]
+    else:
+        name, f = None, {"url": url, "sha256": None, "size": None, "exe": None}
+    _, host, _, _ = check_url(f["url"], allow_local)
+    fname = file_name(f["url"])
+    kind = file_kind(fname)
+    size = f["size"] or _head_size(f["url"], allow_local)
+    if size is not None and size > MAX_FILE:
+        raise WebInstallError(f"{fname} is {size / 1024**3:.1f} GB; the limit is {MAX_FILE / 1024**3:.0f} GB")
+    return {"name": name or fname, "url": f["url"], "file": fname, "kind": kind, "kindLabel": KIND_LABEL[kind],
+            "host": host, "linkHost": urlsplit(link).hostname, "size": size, "sha256": f["sha256"],
+            "exe": f["exe"], "source": link, "allowLocal": allow_local, "sizeFromManifest": bool(f["size"])}
+
+
+def abort(conn):
+    """Stop conn from another thread (cancel, shutdown): unblocks a read, or makes the connect fail."""
+    conn.aborted = True
+    sock = conn.raw_sock
+    if sock is not None:
+        try:
+            sock.shutdown(socket.SHUT_RDWR)
+        except OSError:
+            pass
+
+
+def download(p, dest_dir, progress=None, cancelled=None, connected=None):
+    """Download plan p's file into dest_dir; returns its path. Checks the size cap and sha256.
+
+    progress(done, total_or_None) is called as bytes arrive; cancelled() may return True to stop;
+    connected(conn) gets each connection before it's used, for abort().
+    """
+    dest = os.path.join(dest_dir, p["file"])
+    try:
+        conn, r = _open(p["url"], p["allowLocal"], connected=connected)
+    except WebInstallError:
+        if cancelled and cancelled():
+            raise Cancelled("download cancelled")
+        raise
+    fd, part = tempfile.mkstemp(prefix=".part-", dir=dest_dir)
+    out = os.fdopen(fd, "wb")
+    ok = False
+    try:
+        total = _length(r)
+        expected = p["size"] if p.get("sizeFromManifest") else None
+        if total is not None and total > MAX_FILE:
+            raise WebInstallError(f"the file is over the {MAX_FILE / 1024**3:.0f} GB limit")
+        if expected is not None and total is not None and total != expected:
+            raise WebInstallError(f"the server says {total} bytes; the manifest says {expected}")
+        digest = hashlib.sha256()
+        done = 0
+        while True:
+            if cancelled and cancelled():
+                raise Cancelled("download cancelled")
+            try:
+                chunk = r.read(CHUNK)
+            except (OSError, http.client.HTTPException) as e:
+                if cancelled and cancelled():
+                    raise Cancelled("download cancelled")
+                raise WebInstallError(f"download failed: {e}")
+            if not chunk:
+                if cancelled and cancelled():  # abort() makes the read end early
+                    raise Cancelled("download cancelled")
+                break
+            done += len(chunk)
+            if done > MAX_FILE:
+                raise WebInstallError(f"the file is over the {MAX_FILE / 1024**3:.0f} GB limit")
+            digest.update(chunk)
+            out.write(chunk)
+            if progress:
+                progress(done, total or expected)
+        out.close()
+        if total is not None and done != total:
+            raise WebInstallError(f"download cut off at {done} of {total} bytes")
+        if expected is not None and done != expected:
+            raise WebInstallError(f"downloaded {done} bytes; the manifest says {expected}")
+        if p["sha256"] and digest.hexdigest() != p["sha256"]:
+            raise WebInstallError(f"{p['file']} doesn't match the manifest's sha256; not installing it")
+        os.replace(part, dest)
+        ok = True
+        return dest
+    finally:
+        out.close()
+        conn.close()
+        if not ok:
+            try:
+                os.remove(part)
+            except OSError:
+                pass
+
+
+# ---- installing -------------------------------------------------------------
+
+def dispatch(path, name=None, exe=None, progress=None, source=None):
+    """Install a downloaded file with the installer for its type; returns {"message", "kind", "result"}.
+
+    .apk goes to frame_android (its own Lepton instance and Steam shortcut, named by
+    the APK's label); .zip and .exe to frame_titles. The caller has the SSH
+    connection ready.
+    """
+    kind = file_kind(os.path.basename(path))
+    if kind == "apk":
+        import frame_android
+        try:
+            m = frame_android.install(path, source=source or os.path.basename(path))
+        except frame_android.FrameError as e:
+            raise WebInstallError(str(e))
+        return {"message": f"Installed {m['label']} as its own app in the Steam library", "kind": kind, "result": m}
+    try:
+        import frame_titles
+    except ImportError as e:
+        if e.name != "frame_titles":
+            raise
+        raise WebInstallError("Linux/Windows titles need a newer Frame Control")
+    result = frame_titles.install(path, name=name, exe=exe, progress=progress)
+    msg = result.get("message") if isinstance(result, dict) else None
+    return {"message": msg or f"Installed {name or os.path.basename(path)}", "kind": kind, "result": result}
diff --git a/ui/index.html b/ui/index.html
index 320088c..475ea72 100644
--- a/ui/index.html
+++ b/ui/index.html
@@ -221,12 +221,23 @@
   .and-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 2fr); gap: 22px; align-items: start; }
   .and-col { display: grid; gap: 22px; align-content: start; }
   .rep-item .s { white-space: normal; }
-  #repDlg { background: #1e2329; color: var(--text); border: 1px solid rgba(255,255,255,.1); border-radius: 4px;
+  #repDlg, #titleDlg, #wiDlg { background: #1e2329; color: var(--text); border: 1px solid rgba(255,255,255,.1); border-radius: 4px;
             padding: 22px; width: min(560px, 92vw); box-shadow: 0 20px 60px rgba(0,0,0,.6); }
-  #repDlg::backdrop { background: rgba(0,0,0,.55); }
-  #repDlg h2 { margin: 0 0 14px; font-size: 15px; letter-spacing: 1.5px; text-transform: uppercase; color: var(--bright); }
-  #repForm label { display: block; font-size: 12.5px; color: var(--muted); margin-top: 10px; }
-  #repForm label input[type=text], #repForm textarea { margin-top: 5px; }
+  #repDlg::backdrop, #titleDlg::backdrop, #wiDlg::backdrop { background: rgba(0,0,0,.55); }
+  #repDlg h2, #titleDlg h2, #wiDlg h2 { margin: 0 0 14px; font-size: 15px; letter-spacing: 1.5px; text-transform: uppercase; color: var(--bright); }
+  #repForm label, #titleForm label { display: block; font-size: 12.5px; color: var(--muted); margin-top: 10px; }
+  #repForm label input[type=text], #repForm textarea, #titleForm label input, #titleForm label select { margin-top: 5px; }
+  #titleForm select { width: 100%; background: rgba(0,0,0,.28); color: var(--text); border: 1px solid transparent;
+                      border-radius: 3px; padding: 8px 10px; font: inherit; }
+  #titleForm select:focus { outline: none; border-color: var(--blue); }
+  #titleForm .note { font-size: 12.5px; color: var(--muted); margin-top: 10px; }
+  #titleForm .note.warn { color: #d9a23a; }
+  #titleList { margin-top: 8px; }
+  #wiFacts { display: grid; grid-template-columns: max-content 1fr; gap: 6px 14px; margin: 0; font-size: 13.5px; }
+  #wiFacts dt { color: var(--muted); }
+  #wiFacts dd { margin: 0; color: var(--bright); overflow-wrap: anywhere; }
+  #wiWarn { color: var(--muted); font-size: 12.5px; line-height: 1.45; margin: 14px 0 0; }
+  #wiProg:not([hidden]) { display: block; }
   #repForm fieldset { border: 0; padding: 0; margin: 12px 0 0; }
   #repForm legend { font-size: 12.5px; color: var(--muted); padding: 0; margin-bottom: 4px; }
   #repForm label.opt { display: inline-flex; align-items: center; gap: 6px; margin: 4px 14px 0 0; color: var(--text); font-size: 13.5px; }
@@ -458,10 +469,13 @@
       <div class="shelf-head"><h2>Send to Frame</h2></div>
       <div class="drop" id="drop" tabindex="0" role="button" aria-label="Choose files to send">
         <b>Drop files here</b>
-        Files land in <code>~/Downloads</code>. <code>.apk</code> files install as their own Android app.
+        Files land in <code>~/Downloads</code>. <code>.apk</code> files install as their own Android app;
+        a game's <code>.zip</code>, folder or <code>.exe</code> becomes a title in the Steam library.
         <input type="file" id="fileInput" multiple hidden>
       </div>
       <div class="progress" id="prog"><i></i></div>
+      <div class="shelf-head" style="margin-top:16px"><h2>Sideloaded titles</h2><span class="count" id="titleCount"></span></div>
+      <div class="list" id="titleList"><div class="sub">Loading…</div></div>
       <textarea id="clipText" style="margin-top:16px" placeholder="Text to put on the Frame's clipboard…"></textarea>
       <div class="row" style="margin-top:8px">
         <button class="action small" id="clipSend">Send text</button>
@@ -567,6 +581,32 @@
       <button type="submit" class="action small" id="repSave">Save report</button></div>
   </form>
 </dialog>
+<dialog id="titleDlg" aria-labelledby="titleTitle">
+  <form method="dialog" id="titleForm">
+    <h2 id="titleTitle">Add to the Steam library</h2>
+    <div class="sub" id="titleSrc"></div>
+    <label>Name<input type="text" id="titleName" maxlength="120" required></label>
+    <div class="note" id="titleIdNote"></div>
+    <label>Launches<select id="titleExe"></select></label>
+    <label>Runtime<select id="titleRt"></select></label>
+    <div class="note" id="titleNote"></div>
+    <div class="note warn" id="titleWarn"></div>
+    <div class="row rep-actions"><span class="sub" id="titleMsg"></span><span class="spacer"></span>
+      <button type="button" class="small" id="titleCancel">Cancel</button>
+      <button type="button" class="small" id="titlePush">Copy to ~/Downloads instead</button>
+      <button type="submit" class="action small" id="titleInstall">Install</button></div>
+  </form>
+</dialog>
+<dialog id="wiDlg" aria-labelledby="wiTitle">
+  <h2 id="wiTitle">Install from a website</h2>
+  <dl id="wiFacts"></dl>
+  <p id="wiWarn">A website asked Frame Control to install this. Nothing is downloaded until you click Install.
+    Only install software from sites you trust.</p>
+  <div class="progress" id="wiProg" hidden><i></i></div>
+  <div class="row rep-actions"><span class="sub" id="wiMsg"></span><span class="spacer"></span>
+    <button type="button" class="small" id="wiCancel">Cancel</button>
+    <button type="button" class="action small" id="wiGo" disabled>Install</button></div>
+</dialog>
 <div class="toast" id="toast"></div>
 
 <script>
@@ -1022,9 +1062,9 @@ document.querySelectorAll("[data-view]").forEach(b => b.onclick = () => setView(
 document.querySelectorAll("[data-eye]").forEach(b => b.onclick = () => setEye(b.dataset.eye));
 
 // ---- controls ----
-$("refreshAll").onclick = refresh;
+$("refreshAll").onclick = () => { refresh(); loadTitles(); };  // titles too: the Frame may have been asleep at start
 document.addEventListener("keydown", e => {
-  if (e.key === "r" && !e.metaKey && !e.ctrlKey && !/INPUT|TEXTAREA/.test(document.activeElement.tagName)) refresh();
+  if (e.key === "r" && !e.metaKey && !e.ctrlKey && !/INPUT|TEXTAREA|SELECT/.test(document.activeElement.tagName)) $("refreshAll").onclick();
 });
 document.body.addEventListener("click", async (e) => {
   const b = e.target.closest("button");
@@ -1085,7 +1125,12 @@ drop.onkeydown = e => { if (e.key === "Enter" || e.key === " ") { e.preventDefau
 $("fileInput").onchange = () => sendFiles([...$("fileInput").files]);
 ["dragenter", "dragover"].forEach(t => drop.addEventListener(t, e => { e.preventDefault(); drop.classList.add("over"); }));
 ["dragleave", "drop"].forEach(t => drop.addEventListener(t, e => { e.preventDefault(); drop.classList.remove("over"); }));
-drop.addEventListener("drop", e => sendFiles([...e.dataTransfer.files]));
+// Folders only show up as directory entries, and only during the drop event itself.
+drop.addEventListener("drop", e => {
+  const items = [...(e.dataTransfer.items || [])].filter(it => it.kind === "file");
+  const dirs = new Set(items.map((it, i) => it.webkitGetAsEntry && it.webkitGetAsEntry()?.isDirectory ? i : -1).filter(i => i >= 0));
+  sendFiles([...e.dataTransfer.files], dirs);
+});
 function upload(file, mode) {
   return new Promise((resolve, reject) => {
     const xhr = new XMLHttpRequest();
@@ -1105,9 +1150,17 @@ function upload(file, mode) {
     xhr.send(file);
   });
 }
-async function sendFiles(files) {
-  for (const f of files) {
-    if (!f.size) { toast(`${f.name}: folders and empty files aren't supported here; zip the folder first`, true); continue; }
+const TITLE_EXT = /\.(zip|exe)$/i;
+async function sendFiles(files, dirs = new Set()) {
+  for (const [i, f] of files.entries()) {
+    const path = window.frameApp?.pathForFile ? window.frameApp.pathForFile(f) : "";
+    if (dirs.has(i)) {
+      if (path) await sideload(f, path, true);
+      else toast(`${f.name}: zip the folder first (folders need the Frame Control app)`, true);
+      continue;
+    }
+    if (!f.size) { toast(`${f.name}: empty files aren't supported`, true); continue; }
+    if (TITLE_EXT.test(f.name)) { await sideload(f, path); continue; }
     const apk = f.name.toLowerCase().endsWith(".apk");
     await act(apk ? `Install ${f.name}` : `Copy ${f.name} to ~/Downloads`, () => upload(f, apk ? "apk" : "push"));
   }
@@ -1115,6 +1168,143 @@ async function sendFiles(files) {
   refresh();
 }
 
+// ---- sideloaded titles (a Linux or Windows build as a Steam Devkit Game) ----
+const RESERVED_IDS = ["steam", "steamdeckard", "steamvr", "steamvrdeckard", "devkit-steam"];
+function titleId(name) {  // mirrors frame_titles.title_id: the name Steam shows
+  const trim = x => x.replace(/^[_-]+|[_-]+$/g, "");
+  let s = trim(trim(String(name).trim().replace(/[^A-Za-z0-9_-]+/g, "_").replace(/_+/g, "_")).slice(0, 64));
+  if (RESERVED_IDS.includes(s.toLowerCase())) s += "-game";
+  return s;
+}
+const ARCH = { arm64: "ARM64", x86_64: "x86-64", x86: "32-bit x86" };
+function candLabel(c) {
+  const kind = c.format === "pe" ? `Windows ${ARCH[c.arch] || c.arch}` : c.format === "elf" ? `Linux ${ARCH[c.arch] || c.arch}` : "script";
+  return `${c.path} · ${kind} · ${gb(c.size)}${c.skip ? " · helper?" : ""}`;
+}
+// Inspect (upload, or the local path in the app), confirm in the dialog, then install with progress.
+// One at a time, so a second drop doesn't take over the dialog of the first.
+let sideloadQueue = Promise.resolve();
+function sideload(...args) {
+  const run = sideloadQueue.then(() => sideloadOne(...args));
+  sideloadQueue = run.catch(() => {});
+  return run;
+}
+async function sideloadOne(file, path, isDir = false) {
+  const canPush = !isDir && file.size > 0;
+  log(`Reading ${file.name}…`);
+  let r;
+  try { r = path ? await api("/api/titles", { action: "inspect", path }) : await upload(file, "title"); }
+  catch (e) {
+    log(`${file.name}: ${e.message}`, "e");
+    if (canPush && confirm(`${file.name}: ${e.message}\n\nCopy it to ~/Downloads instead?`))
+      await act(`Copy ${file.name} to ~/Downloads`, () => upload(file, "push"));
+    return;
+  }
+  // Its own fresh list, so the dialog can say whether this replaces an installed title.
+  let installed = null;
+  try { installed = new Set((await api("/api/titles")).titles.map(t => String(t.id).toLowerCase())); } catch {}
+  const choice = await confirmTitle(r.plan, canPush, installed);
+  if (choice === "push") {
+    api("/api/titles", { action: "discard", token: r.token }).catch(() => {});
+    await act(`Copy ${file.name} to ~/Downloads`, () => upload(file, "push"));
+    return;
+  }
+  if (!choice) { api("/api/titles", { action: "discard", token: r.token }).catch(() => {}); return; }
+  await installTitle(r.token, choice);
+}
+function confirmTitle(plan, canPush, installed) {  // installed: a Set of lower-case ids, or null if unknown
+  return new Promise(resolve => {
+    const dlg = $("titleDlg");
+    $("titlePush").hidden = !canPush;
+    $("titleSrc").textContent = `${plan.source} · ${gb(plan.size)}`;
+    $("titleName").value = plan.name;
+    const idNote = () => { const id = titleId($("titleName").value);
+      $("titleIdNote").textContent = !id ? "Needs some letters or digits"
+        : !installed ? `Shows in Steam as ${id}. Couldn't check whether it's installed already; if it is, this replaces it`
+        : installed.has(id.toLowerCase()) ? `Replaces the installed ${id}, and everything in its folder on the Frame`
+        : `Shows in Steam as ${id}`; };
+    $("titleName").oninput = idNote; idNote();
+    $("titleExe").innerHTML = plan.candidates.map(c =>
+      `<option value="${esc(c.path)}"${c.path === plan.target ? " selected" : ""}${c.blocked ? " disabled" : ""}>${esc(candLabel(c))}</option>`).join("");
+    const runtimes = () => {
+      const c = plan.candidates.find(x => x.path === $("titleExe").value) || {};
+      const list = c.runtimes || [];
+      $("titleRt").innerHTML = list.map(k => `<option value="${esc(k)}">${esc(plan.runtime_labels[k] || k)}</option>`).join("");
+      $("titleRt").disabled = list.length < 2;
+      if (c.path === plan.target) {
+        $("titleRt").value = plan.runtime;
+        $("titleNote").textContent = plan.note + " Device behaviour is inferred from Valve's devkit tools.";
+      } else $("titleNote").textContent = "Runtime follows the chosen program.";
+      $("titleWarn").textContent = c.skip ? "This looks like an installer or helper, not the game itself." : "";
+    };
+    $("titleExe").onchange = runtimes; runtimes();
+    $("titleMsg").textContent = "";
+    // Resolve on this dialog's own close event (it arrives a frame later), so a
+    // queued next title can't receive it. Escape closes with the choice left null.
+    let choice = null;
+    dlg.addEventListener("close", () => resolve(choice), { once: true });
+    const finish = v => { choice = v; dlg.close(); };
+    $("titleCancel").onclick = () => finish(null);
+    $("titlePush").onclick = () => finish("push");
+    $("titleForm").onsubmit = e => {
+      e.preventDefault();
+      if (!titleId($("titleName").value)) return ($("titleMsg").textContent = "Enter a name");
+      finish({ name: $("titleName").value.trim(), exe: $("titleExe").value, runtime: $("titleRt").value });
+    };
+    dlg.showModal();
+    $("titleName").focus();
+  });
+}
+async function installTitle(token, choice) {
+  const label = `Install ${titleId(choice.name)}`;
+  const start = await act(label, () => api("/api/titles", { action: "install", token, ...choice }));
+  if (!start) return;
+  const bar = $("prog").firstElementChild;
+  $("prog").style.display = "block"; bar.style.width = "0";
+  let stage = "";
+  try {
+    for (;;) {
+      await new Promise(ok => setTimeout(ok, 1000));
+      let j;
+      try { j = await api(`/api/titles/job?token=${encodeURIComponent(start.job)}`); }
+      catch (e) { log(`${label}: ${e.message}`, "e"); return; }
+      bar.style.width = (100 * (j.fraction || 0)) + "%";
+      if (j.stage && j.stage !== stage && !j.done) { stage = j.stage; log(`${stage}…`); $("lastLog").textContent = stage + "…"; }
+      if (j.done) {
+        if (j.error) { log(`${label} failed: ${j.error}`, "e"); toast(`${label} failed: ${j.error}`, true); }
+        else { log(j.message, "ok"); toast(j.message); }
+        break;
+      }
+    }
+  } finally { $("prog").style.display = "none"; loadTitles(); }
+}
+let titlesSeq = 0;  // a slower, older request mustn't overwrite a newer list
+async function loadTitles() {
+  const seq = ++titlesSeq;
+  let list, err;
+  try { list = (await api("/api/titles")).titles; } catch (e) { err = e; }
+  if (seq !== titlesSeq) return;
+  if (err) { $("titleList").innerHTML = `<div class="sub">${esc(err.message)}</div>`; return; }
+  $("titleCount").textContent = list.length ? `${list.length}` : "";
+  $("titleList").innerHTML = list.length ? list.map(t => `
+    <div class="item">
+      <div class="grow"><div class="t">${esc(t.id)}</div>
+        <div class="s" title="${esc(t.target)}">${esc(t.runtime_label)}${t.target ? " · " + esc(t.target) : ""}</div></div>
+      <button class="play small" data-title="launch" data-id="${esc(t.id)}" title="Launch in the headset">▶</button>
+      <button class="small danger" data-title="remove" data-id="${esc(t.id)}">Remove</button>
+    </div>`).join("") : `<div class="sub">None yet. Drop a game's .zip, folder or .exe above.</div>`;
+}
+$("titleList").onclick = async e => {
+  const b = e.target.closest("[data-title]"); if (!b) return;
+  const id = b.dataset.id;
+  if (b.dataset.title === "remove") {
+    if (!confirm(`Remove ${id} and its files from the Frame?`)) return;
+    await act(`Remove ${id}`, () => api("/api/titles", { action: "remove", id }), b);
+    loadTitles();
+  } else await act(`Launch ${id}`, () => api("/api/titles", { action: "launch", id }), b);
+};
+loadTitles();
+
 
 // ---- Steam games: install owned games, find and buy on the store ----
 const FLABEL = { 3: "Frame Verified", 2: "Playable", 1: "Unsupported", 0: "Unknown" };
@@ -1632,6 +1822,110 @@ const spy = new IntersectionObserver(entries => {
 }, { rootMargin: "-80px 0px -55% 0px" });
 ["view", "shots", "library", "getgames", "android", "transfer", "apps", "display", "power"].forEach(id => spy.observe($(id)));
 
+// ---- install links from websites (frame-control://install, docs/web-install.md) ----
+// The app passes each link here. The server checks it and reads the manifest;
+// nothing downloads until the user clicks Install in this dialog.
+const wi = { queue: [], open: false, gen: 0, plan: null, job: null, starting: false };
+function wiSize(n) {
+  if (n == null) return "Not given";
+  return n >= 1e9 ? gb(n) : n >= 1e6 ? (n / 1e6).toFixed(1) + " MB" : Math.max(1, Math.round(n / 1e3)) + " KB";
+}
+function wiFacts(rows) { $("wiFacts").innerHTML = rows.map(([k, v]) => `<dt>${esc(k)}</dt><dd>${esc(v)}</dd>`).join(""); }
+function wiButtons(cancel, go) {
+  $("wiCancel").textContent = cancel[0]; $("wiCancel").disabled = !cancel[1];
+  $("wiGo").hidden = !go; $("wiGo").disabled = go !== "on";
+}
+async function wiNext() {
+  if (wi.open || !wi.queue.length) return;
+  const req = wi.queue.shift(), gen = ++wi.gen;
+  wi.open = true; wi.plan = null; wi.job = null;
+  let host = "";
+  try { host = new URL(req.target).hostname; } catch {}
+  wiFacts([["From", host], [req.kind === "manifest" ? "Manifest" : "File", req.target]]);
+  $("wiProg").hidden = true; $("wiMsg").textContent = "Checking the link…";
+  wiButtons(["Cancel", true], "off");
+  $("wiDlg").showModal();
+  log(`Install link from ${host}`);
+  try {
+    const p = await api("/api/webinstall/check", { [req.kind]: req.target });
+    if (gen !== wi.gen) return;
+    wi.plan = p;
+    const from = p.host === p.linkHost ? p.host : `${p.linkHost} (file on ${p.host})`;
+    wiFacts([["Title", p.name], ["From", from], ["File", p.file], ["Type", p.kindLabel], ["Size", wiSize(p.size)],
+             ["SHA-256", p.sha256 ? "Given; checked after downloading" : "Not given; the download can't be checked"]]);
+    $("wiMsg").textContent = "";
+    wiButtons(["Cancel", true], "on");
+    $("wiGo").focus();
+  } catch (e) {
+    if (gen !== wi.gen) return;
+    $("wiMsg").textContent = e.message;
+    wiButtons(["Close", true], null);
+    log(`Install link refused: ${e.message}`, "e");
+  }
+}
+async function wiPoll(gen) {
+  if (gen !== wi.gen || !wi.job) return;
+  let j;
+  try {
+    j = await api(`/api/webinstall/job?id=${encodeURIComponent(wi.job)}`);
+  } catch (e) {
+    $("wiMsg").textContent = e.message;
+    return setTimeout(() => wiPoll(gen), 1500);
+  }
+  if (gen !== wi.gen) return;
+  const bar = $("wiProg").firstElementChild;
+  $("wiProg").hidden = false;
+  if (j.phase === "download") {
+    bar.style.width = j.total ? (100 * j.done / j.total) + "%" : "0";
+    $("wiMsg").textContent = `Downloading ${wiSize(j.done)}` + (j.total ? ` of ${wiSize(j.total)}` : "");
+    wiButtons(["Stop download", true], "off");
+  } else if (j.phase === "install") {
+    bar.style.width = "100%";
+    $("wiMsg").textContent = j.detail || "Installing on the Frame…";
+    wiButtons(["Stop download", false], "off");
+  } else {
+    wi.job = null;
+    $("wiProg").hidden = true;
+    if (j.phase === "done") {
+      log(j.message, "ok"); toast(j.message);
+      $("wiDlg").close();
+      loadAndroid(); loadTitles(); refresh();
+    } else {
+      $("wiMsg").textContent = j.error;
+      log(`Install from link failed: ${j.error}`, "e"); toast(`Install failed: ${j.error}`, true);
+      wiButtons(["Close", true], null);
+    }
+    return;
+  }
+  setTimeout(() => wiPoll(gen), 500);
+}
+$("wiGo").onclick = async () => {
+  const p = wi.plan, gen = wi.gen;
+  if (!p) return;
+  wi.plan = null;  // one click, one install
+  wiButtons(["Cancel", false], "off");
+  $("wiMsg").textContent = "Starting…";
+  wi.starting = true;  // the dialog stays open until the job is known
+  try {
+    wi.job = (await api("/api/webinstall/start", { id: p.id })).job;
+    log(`Installing ${p.name} from ${p.host}…`);
+    wiPoll(gen);
+  } catch (e) {
+    $("wiMsg").textContent = e.message;
+    wiButtons(["Close", true], null);
+  } finally { wi.starting = false; }
+};
+$("wiCancel").onclick = async () => {
+  if (!wi.job) return $("wiDlg").close();
+  try { await api("/api/webinstall/cancel", { job: wi.job }); } catch (e) { $("wiMsg").textContent = e.message; }
+};
+// Escape doesn't close the dialog while an install runs; it keeps showing progress.
+$("wiDlg").addEventListener("cancel", e => { if (wi.job || wi.starting) e.preventDefault(); });
+$("wiDlg").addEventListener("close", () => { wi.gen++; wi.open = false; wi.plan = null; wi.job = null; setTimeout(wiNext); });
+if (window.frameApp && window.frameApp.onInstallLink) {
+  window.frameApp.onInstallLink(req => { if (wi.queue.length < 5) wi.queue.push(req); wiNext(); });
+}
+
 setView("headset");
 refresh().then(loadShots);  // after status, so app names resolve
 setInterval(() => { if (!document.hidden) refresh(); }, 30000);
diff --git a/ui/server.py b/ui/server.py
index 60bbcef..05661e3 100755
--- a/ui/server.py
+++ b/ui/server.py
@@ -15,6 +15,7 @@ import json
 import os
 import queue
 import re
+import secrets
 import shlex
 import shutil
 import signal
@@ -36,6 +37,8 @@ import frame_android  # noqa: E402
 import frame_catalog  # noqa: E402
 import frame_host  # noqa: E402
 import frame_store  # noqa: E402
+import frame_titles  # noqa: E402
+import frame_webinstall  # noqa: E402
 
 frame_host.trust_bundled_cas()
 
@@ -472,6 +475,120 @@ def android(body):
     raise Failure("unknown action", 400)
 
 
+# ---- Sideloaded titles (Linux/Windows builds as Steam Devkit Games) --------
+#
+# Installing is two steps: inspect (a dropped file is uploaded and a zip
+# unpacked here, once) returns a token and the detected target and runtime for
+# the page to confirm; install then runs in the background with progress the
+# page polls. Unconfirmed uploads are dropped after STAGE_TTL.
+
+STAGE_TTL = 3600
+_titles_lock = threading.Lock()
+_staged = {}  # token -> {"plan", "dir" (an upload's temp dir or None), "time"}
+_title_jobs = {}  # token -> {"stage", "fraction", "done", "error", "title", "time"}
+
+
+def _drop_staged(entry):
+    frame_titles.discard(entry["plan"])
+    if entry.get("dir"):
+        shutil.rmtree(entry["dir"], ignore_errors=True)
+
+
+def _purge_titles(now=None):
+    now = now or time.time()
+    with _titles_lock:
+        stale = [_staged.pop(t) for t in [t for t, e in _staged.items() if now - e["time"] > STAGE_TTL]]
+        for t in [t for t, j in _title_jobs.items() if j["done"] and now - j["time"] > STAGE_TTL]:
+            del _title_jobs[t]
+    for e in stale:
+        _drop_staged(e)
+
+
+def stage_title(path, temp_dir=None, name=None):
+    """Inspect a .zip, folder or program and keep it for install; returns the plan and a token."""
+    _purge_titles()
+    try:
+        plan = frame_titles.inspect(path, name)
+    except BaseException as e:
+        # Whatever went wrong, nothing will ever claim this upload.
+        if temp_dir:
+            shutil.rmtree(temp_dir, ignore_errors=True)
+        if isinstance(e, frame_android.FrameError):
+            raise Failure(str(e), 400)
+        raise
+    token = secrets.token_hex(12)
+    with _titles_lock:
+        _staged[token] = {"plan": plan, "dir": temp_dir, "time": time.time()}
+    return {"message": f"Read {plan['source']}: {plan['target']} with {plan['runtime_label']}",
+            "token": token, "plan": frame_titles.public(plan)}
+
+
+def _run_title_install(token, entry, name, exe, runtime):
+    def update(**fields):  # the page reads jobs from other threads; change them under the lock
+        with _titles_lock:
+            _title_jobs[token].update(fields)
+
+    try:
+        m = frame_titles.install_plan(entry["plan"], name=name, exe=exe, runtime=runtime,
+                                      progress=lambda stage, fraction: update(stage=stage, fraction=fraction))
+        update(title=m, message=f"Installed {m['id']} in the Steam library ({m['runtime_label']})")
+    except frame_android.FrameError as e:
+        update(error=str(e))
+    except Exception as e:
+        update(error=f"{type(e).__name__}: {e}")
+    finally:
+        _drop_staged(entry)
+        update(done=True, time=time.time())
+
+
+def titles(body):
+    """Sideloaded titles (frame_titles.py): inspect a local path, install, discard, launch, remove."""
+    action = body.get("action")
+    if action == "inspect":
+        # The app's page passes a dropped folder's path (Electron knows it); browsers upload instead.
+        path = str(body.get("path") or "")
+        if not os.path.isabs(path) or not os.path.exists(path):
+            raise Failure("inspect needs the absolute path of a .zip, folder or program", 400)
+        return stage_title(path, name=body.get("name") or None)
+    if action in ("install", "discard"):
+        token = str(body.get("token") or "")
+        with _titles_lock:
+            entry = _staged.pop(token, None)
+        if not entry:
+            raise Failure("that upload has expired; drop the file again", 400)
+        if action == "discard":
+            _drop_staged(entry)
+            return {"message": "Discarded"}
+        with _titles_lock:
+            _title_jobs[token] = {"stage": "Starting", "fraction": 0, "done": False, "error": None,
+                                  "message": None, "title": None, "time": time.time()}
+        ensure_master()
+        opt = lambda k: str(body.get(k) or "") or None  # noqa: E731
+        threading.Thread(target=_run_title_install, daemon=True,
+                         args=(token, entry, opt("name"), opt("exe"), opt("runtime"))).start()
+        return {"message": f"Installing {entry['plan']['source']}", "job": token}
+    if action not in ("launch", "remove"):
+        raise Failure("unknown action", 400)
+    gid = str(body.get("id", ""))
+    if not frame_titles.ID_RE.match(gid):
+        raise Failure("bad title id", 400)
+    ensure_master()
+    try:
+        m = getattr(frame_titles, action)(gid)
+    except frame_android.FrameError as e:
+        raise Failure(str(e))
+    return {"message": f"{'Launching' if action == 'launch' else 'Removed'} {m['id']}"}
+
+
+def title_job(query):
+    with _titles_lock:
+        job = _title_jobs.get((parse_qs(query).get("token") or [""])[0])
+        snapshot = job and {k: v for k, v in job.items() if k != "time"}
+    if not snapshot:
+        raise Failure("no such install", 404)
+    return snapshot
+
+
 # ---- Android display (wm size / wm density / font_scale over ADB) -----------
 #
 # Each running Lepton instance listens for ADB on the Frame (5555 is Lepton
@@ -762,8 +879,197 @@ def android_display(body):
     return {"message": f"Port {port}: " + "; ".join(c.split(";")[0] for c in cmds), "display": now}
 
 
-POST = {"/api/android/display": android_display, "/api/android": android,"/api/launch": launch, "/api/steam": steam, "/api/volume": set_volume, "/api/clipboard": clipboard,
-        "/api/flatpak": flatpak, "/api/open": open_thing, "/api/shots/save": save_shots}
+# ---- install links from websites (frame-control://install, docs/web-install.md) ----
+# The app hands the link to the page, which asks /check (fetches the manifest,
+# downloads nothing), shows what it found and waits for the user's click before
+# /start. A website can't call these itself: like all of /api/* they need the
+# Host and X-Frame-UI checks in Handler.local_request.
+_web_lock = threading.Lock()
+_web_plans = {}   # id -> checked plan waiting for the user to confirm
+_web_jobs = {}    # id -> progress of the confirmed install (only the latest is kept)
+_web_workers = set()  # threads running an install, joined on shutdown
+_web_closing = False  # set on shutdown; no new installs after that
+MAX_WEB_PLANS = 8
+WEB_TMP_PREFIX = "frame-webinstall-"  # then the server's PID, for sweep_tmp
+
+
+def webinstall_check(body):
+    manifest, url = body.get("manifest"), body.get("url")
+    for v in (manifest, url):
+        if v is not None and not isinstance(v, str):
+            raise Failure("manifest and url must be strings", 400)
+    try:
+        plan = frame_webinstall.plan(manifest=manifest, url=url)
+    except frame_webinstall.WebInstallError as e:
+        raise Failure(str(e), 400)
+    pid = secrets.token_urlsafe(16)
+    with _web_lock:
+        while len(_web_plans) >= MAX_WEB_PLANS:
+            _web_plans.pop(next(iter(_web_plans)))
+        _web_plans[pid] = plan
+    shown = ("name", "file", "kind", "kindLabel", "host", "linkHost", "size", "source")
+    return {"id": pid, **{k: plan[k] for k in shown}, "sha256": bool(plan["sha256"])}
+
+
+def webinstall_start(body):
+    pid = body.get("id")
+    with _web_lock:
+        if any(j["phase"] in ("download", "install") for j in _web_jobs.values()):
+            raise Failure("another install from a link is still running", 409)
+        # One use per check: the page can only install what it showed.
+        plan = _web_plans.pop(pid, None) if isinstance(pid, str) else None
+        if not plan:
+            raise Failure("unknown or already used install id; open the link again", 400)
+        job = {"phase": "download", "done": 0, "total": plan["size"], "detail": "", "message": None,
+               "error": None, "cancel": False}
+        if _web_closing:
+            raise Failure("Frame Control is quitting", 503)
+        _web_jobs.clear()
+        _web_jobs[pid] = job
+        # Started under the lock, so shutdown never sees a thread it can't join.
+        worker = threading.Thread(target=_webinstall_run, args=(plan, job), daemon=True)
+        _web_workers.add(worker)
+        worker.start()
+    return {"job": pid}
+
+
+def _webinstall_run(plan, job):
+    tmp = None
+    try:
+        tmp = tempfile.mkdtemp(prefix=f"{WEB_TMP_PREFIX}{os.getpid()}-")
+
+        def progress(done, total):
+            job["done"], job["total"] = done, total
+
+        def detail(*args, **_kw):  # frame_titles may report its steps as text
+            texts = [a for a in args if isinstance(a, str)]
+            if texts:
+                job["detail"] = texts[0][:200]
+
+        def connected(conn):
+            with _web_lock:
+                job["_conn"] = conn
+                stop = job["cancel"]  # cancelled before this connection existed
+            if stop:
+                frame_webinstall.abort(conn)
+
+        path = frame_webinstall.download(plan, tmp, progress=progress, cancelled=lambda: job["cancel"],
+                                         connected=connected)
+        # Under the lock cancel uses, so a cancel it acknowledged is never followed by an install.
+        with _web_lock:
+            if job["cancel"]:
+                raise frame_webinstall.Cancelled("download cancelled")
+            job["phase"] = "install"
+            job.pop("_conn", None)
+        ensure_master()
+        res = frame_webinstall.dispatch(path, name=plan["name"], exe=plan["exe"], progress=detail, source=plan["url"])
+        job["message"], job["phase"] = res["message"], "done"
+    except Exception as e:
+        known = (frame_webinstall.WebInstallError, Failure, frame_android.FrameError)
+        job["error"] = str(e) if isinstance(e, known) else f"{type(e).__name__}: {e}"
+        job["phase"] = "error"
+    finally:
+        with _web_lock:
+            job.pop("_conn", None)
+        if tmp:
+            shutil.rmtree(tmp, ignore_errors=True)
+        with _web_lock:
+            _web_workers.discard(threading.current_thread())
+
+
+def webinstall_job(query):
+    job = _web_jobs.get((parse_qs(query).get("id") or [""])[0])
+    if not job:
+        raise Failure("unknown install job", 404)
+    with _web_lock:  # the worker adds and drops _conn meanwhile
+        return {k: v for k, v in job.items() if k != "cancel" and not k.startswith("_")}
+
+
+def webinstall_cancel(body):
+    jid = body.get("job")
+    job = _web_jobs.get(jid) if isinstance(jid, str) else None
+    if not job:
+        raise Failure("unknown install job", 404)
+    with _web_lock:
+        if job["phase"] != "download":
+            raise Failure("only the download can be cancelled", 409)
+        job["cancel"] = True
+        conn = job.get("_conn")
+    if conn:
+        frame_webinstall.abort(conn)
+    return {"message": "Cancelling the download"}
+
+
+def webinstall_shutdown():
+    """Stop downloads and give workers a moment to delete their temporary files.
+
+    An install already copying to the Frame may outlive this; sweep_tmp
+    removes what it leaves on a later start.
+    """
+    global _web_closing
+    with _web_lock:
+        _web_closing = True
+        conns = []
+        for job in _web_jobs.values():
+            job["cancel"] = True
+            conns.append(job.get("_conn"))  # once: the worker may drop it any time
+        workers = list(_web_workers)
+    for conn in conns:
+        if conn:
+            frame_webinstall.abort(conn)
+    deadline = time.time() + 4  # the app kills the server 5 s after asking it to stop
+    for worker in workers:
+        worker.join(max(0, deadline - time.time()))
+
+
+def _pid_alive(pid):
+    if frame_host.WINDOWS:
+        # os.kill(pid, 0) would terminate the process there; ask the kernel instead.
+        import ctypes
+        k32 = ctypes.WinDLL("kernel32", use_last_error=True)
+        handle = k32.OpenProcess(0x1000, False, pid)  # PROCESS_QUERY_LIMITED_INFORMATION
+        if not handle:
+            return ctypes.get_last_error() == 5  # access denied: it exists
+        try:
+            code = ctypes.c_ulong()
+            return not k32.GetExitCodeProcess(handle, ctypes.byref(code)) or code.value == 259  # STILL_ACTIVE
+        finally:
+            k32.CloseHandle(handle)
+    try:
+        os.kill(pid, 0)
+    except ProcessLookupError:
+        return False
+    except OSError:
+        return True  # exists, owned by someone else
+    return True
+
+
+def sweep_tmp():
+    """Delete download and title staging folders left by a server killed mid-install.
+
+    Folders carry the server's PID, so only a dead server's are taken.
+    """
+    for prefix in (WEB_TMP_PREFIX, frame_titles.TMP_PREFIX):
+        for d in Path(tempfile.gettempdir()).glob(f"{prefix}*"):
+            _sweep_one(prefix, d)
+
+
+def _sweep_one(prefix, d):
+    m = re.fullmatch(re.escape(prefix) + r"(\d+)-.*", d.name)
+    if not m:
+        return
+    pid = int(m[1])
+    try:
+        if pid != os.getpid() and not _pid_alive(pid) and d.is_dir():
+            shutil.rmtree(d, ignore_errors=True)
+    except OSError:
+        pass
+
+
+POST = {"/api/android/display": android_display, "/api/android": android, "/api/titles": titles, "/api/launch": launch, "/api/steam": steam, "/api/volume": set_volume, "/api/clipboard": clipboard,
+        "/api/flatpak": flatpak, "/api/open": open_thing, "/api/shots/save": save_shots,
+        "/api/webinstall/check": webinstall_check, "/api/webinstall/start": webinstall_start,
+        "/api/webinstall/cancel": webinstall_cancel}
 
 
 # ---- HTTP ------------------------------------------------------------------
@@ -864,6 +1170,11 @@ class Handler(BaseHTTPRequestHandler):
             elif path == "/api/android":
                 ensure_master()
                 self.send_json({"apps": frame_android.list_apps()})
+            elif path == "/api/titles":
+                ensure_master()
+                self.send_json({"titles": frame_titles.list_titles()})
+            elif path == "/api/titles/job":
+                self.send_json(title_job(url.query))
             elif path == "/api/android/displays":
                 self.send_json(android_displays())
             elif path == "/api/android/reports":
@@ -877,6 +1188,8 @@ class Handler(BaseHTTPRequestHandler):
                 self.send_json(steam_frame("owned"))
             elif path == "/api/steam/search":
                 self.send_json(steam_search(url.query))
+            elif path == "/api/webinstall/job":
+                self.send_json(webinstall_job(url.query))
             elif path == "/api/shots":
                 self.send_json(list_shots())
             elif path == "/api/shots/image":
@@ -982,7 +1295,8 @@ class Handler(BaseHTTPRequestHandler):
             _live_tunnels.discard(proc)
 
     def upload(self):
-        """Raw file body. X-Filename names it; X-Mode is 'push', 'apk' (install) or 'apkinfo' (read only)."""
+        """Raw file body. X-Filename names it; X-Mode is 'push', 'apk' (install), 'apkinfo' (read only)
+        or 'title' (a .zip or program to sideload: inspected and kept for /api/titles install)."""
         name = os.path.basename(unquote(self.headers.get("X-Filename", "")))
         mode = self.headers.get("X-Mode", "push")
         length = int(self.headers.get("Content-Length") or 0)
@@ -993,6 +1307,7 @@ class Handler(BaseHTTPRequestHandler):
         if mode in ("apk", "apkinfo") and not name.lower().endswith(".apk"):
             raise Failure("APK install needs a .apk file", 400)
         tmp = Path(tempfile.mkdtemp(prefix="frame-ui-"))
+        keep = False
         try:
             dest = tmp / name
             with open(dest, "wb") as f:
@@ -1016,6 +1331,9 @@ class Handler(BaseHTTPRequestHandler):
                 except frame_android.FrameError as e:
                     info["blocker"] = str(e)
                 return {"message": f"Read {info['label']} {info['version']}", "apk": info}
+            if mode == "title":
+                keep = True  # stage_title owns tmp now, and removes it on failure
+                return stage_title(str(dest), temp_dir=str(tmp))
             if mode == "apk":
                 ensure_master()
                 try:
@@ -1025,7 +1343,8 @@ class Handler(BaseHTTPRequestHandler):
                 return {"message": f"Installed {m['label']} as its own app in the Steam library", "app": m}
             return {"message": push_file(dest)}
         finally:
-            shutil.rmtree(tmp, ignore_errors=True)
+            if not keep:
+                shutil.rmtree(tmp, ignore_errors=True)
 
 
 def main():
@@ -1036,6 +1355,7 @@ def main():
                          "Windows has no SIGTERM to catch)")
     args = ap.parse_args()
     httpd = ThreadingHTTPServer(("127.0.0.1", args.port), Handler)
+    sweep_tmp()
     if not frame_host.WINDOWS:
         signal.signal(signal.SIGTERM, lambda *_: (_ for _ in ()).throw(KeyboardInterrupt))
     if args.exit_on_eof:
@@ -1053,6 +1373,7 @@ def main():
         # mid-cleanup would abort it and leave the SSH master running.
         if not frame_host.WINDOWS:
             signal.signal(signal.SIGTERM, signal.SIG_IGN)
+        webinstall_shutdown()
         # The master was started with -N, so it stays up until told to exit.
         if CONTROL:
             subprocess.run([*MUX, "-O", "exit", FRAME], capture_output=True, stdin=subprocess.DEVNULL)
@@ -1061,6 +1382,7 @@ def main():
         for proc in list(_live_tunnels):  # ADB forwards and video streams cut off mid-way
             if proc.poll() is None:
                 proc.terminate()
+        _purge_titles(now=float("inf"))  # unconfirmed title uploads
 
 
 if __name__ == "__main__":