The workflow installed only Chromium and ran chromium-desktop + chromium-mobile.
iOS Safari is the app's stated primary user — a wedding guest opening a QR link —
and WebKit is the only engine in the matrix that reproduces two of its behaviours:
- it enforces X-Frame-Options on the hidden download iframe, so a site-wide DENY
makes the keepsake download silently do nothing. Blink hands attachments to
the download manager before the frame check and never notices.
- it abandons a <video> load unless its Range probe gets a 206.
Both of those shipped. Adding 06-export to the webkit project in the round-1 fix
bought nothing on a PR, because CI never ran that project at all — the regression
test written specifically to catch the blocker only ever executed locally.
Runs 71 tests (67 pass, 4 skip on the documented IndexedDB-blob harness
limitation) in ~1.5 minutes locally, using the exact command added here.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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