Carryover evaluation for Web Compat

[nairnandu]

Original proposal(s): #884, #825, #855, #856, #857, #858, #710

Tests

• All tests
• Failing tests

We should also consider whether we add tests for Web Compat focus area in Interop 2026.

[jakearchibald]

This seems like… lots of different things 😄

[jgraham]

In experimental the failures are https://wpt.fyi/results/?label=master&label=experimental&aligned&view=interop&q=label%3Ainterop-2025-webcompat%20status%3A%21ok%20status%3A%21pass

For Firefox there's one test which has subtests failing in Stable but not in Experimental: https://wpt.fyi/results/shadow-dom/Document-caretPositionFromPoint.tentative.html?label=master&label=stable&aligned&view=interop&q=label%3Ainterop-2025-webcompat%20status%3A%21ok%20status%3A%21pass

That's because https://bugzilla.mozilla.org/show_bug.cgi?id=1914596 hasn't landed yet. It's blocked on two things:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1550635 because without that enabling the shadow DOM behaviour caused compat problems. However the spec for caretRangeFromPoint is still missing: [cssom-view-1] Define caretRangeFromPoint() w3c/csswg-drafts#12362
• https://bugzilla.mozilla.org/show_bug.cgi?id=2000473 which is about how client rects work for elements outside the visual viewport but inside the layout viewport.

So from the point of view of carry-over one question is the level of commitment we have to getting the relevant spec changes merged. This is an area where we'd like to improve interop, but it fundamentally depends on having reliable specifications.

[wpt-interop]

Thank you for proposing Carryover evaluation for Web Compat for Interop 2026.

We are pleased to let you know that it has been accepted as part of the CSS zoom focus area.

You’ll be able to track progress on this topic throughout the year via the Interop 2026 dashboard.

Posted on behalf of the Interop team.