From the review of the parser change: scripts typed text/ecmascript,
application/x-javascript and the other JavaScript MIME types run as classic
scripts too, so they're checked now. And the duplicate-name check (V8 only)
no longer skips with the var check when a Node lacks acorn.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>