Feature: :where() Reference: https://github.com/web-platform-dx/web-features/blob/main/features/where.yml Note: The :where() CSS functional pseudo-class takes a selector list as its argument, and matches any element that can be selected by one of the selectors in that list. It is functionally equivalent to the selectors in the list, but doesn't affect the CSS rule specificity (zero specificity). Search strategy: Searched for ":where" selector usage and "zero-matches" spec anchor references. Results: - Total matches found: 143 across 45 unique files - Filtered: 18 files mapped WEB_FEATURES.yml files created/updated: ✅ [css/selectors/WEB_FEATURES.yml](css/selectors/WEB_FEATURES.yml) - Root-level :where() tests (10 files) - **UPDATED** ✅ [css/selectors/invalidation/WEB_FEATURES.yml](css/selectors/invalidation/WEB_FEATURES.yml) - :where() invalidation tests (3 files) - **UPDATED** ✅ [css/selectors/parsing/WEB_FEATURES.yml](css/selectors/parsing/WEB_FEATURES.yml) - :where() parsing tests (2 files) - **UPDATED** ✅ [css/selectors/query/WEB_FEATURES.yml](css/selectors/query/WEB_FEATURES.yml) - :where() querySelector test (1 file) - **CREATED** ✅ [css/cssom/WEB_FEATURES.yml](css/cssom/WEB_FEATURES.yml) - :where() CSSOM crash test (1 file) - **UPDATED** Excluded (27 files): - @scope tests (7 files): Primary focus on @scope cascade behavior - @supports tests (3 files): Primary focus on @supports selector() functionality - Nesting tests (3 files): Primary focus on CSS nesting behavior - Mixins tests (2 files): Primary focus on CSS mixins functionality - :has() tests (3 files): Primary focus on :has() selector (parse-has-*, has-sibling-chrome-crash, invalidation test) - :is() test (1 file): query-is.html is about :is(), not :where() - :not() specificity test (1 file): Primary focus on :not() specificity behavior - Scoping/shadow parts (2 files): Primary focus on ::slotted and ::part - ::part parsing (1 file): Primary focus on ::part pseudo-element - Container queries (1 file): Primary focus on container queries - Scroll animations (1 file): Primary focus on scroll timeline animations

Classifies web features from "window-controls-overlay" to "webxr-hit-test"#55663ChrisC wants to merge 11 commits intoweb-platform-tests:masterweb-platform-tests/wpt:masterfrom bocoup:web-features-wi-webocoup/wpt:web-features-wi-weCopy head branch name to clipboard

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Commits on Oct 23, 2025

Commits on Oct 27, 2025

Classifies web features from "window-controls-overlay" to "webxr-hit-test"#55663
ChrisC wants to merge 11 commits intoweb-platform-tests:masterfrom
bocoup:web-features-wi-we