Web Inspector

• Elements Tab
  • Added badges for CSS Grid container elements (r273097)
  • Layout details sidebar panel
    • Implemented grid overlay options (r272918, r272948, r273098, r273155, r273164, r273185, r273847)
    • Show a list of CSS Grid container elements in the Layout sidebar panel (r272934, r272976, r273502)
• Audits Tab
  • Fixed clicking the “Start” button in the content area placeholder text (r273900)

Animations

• Changed CSS properties that disallow negative values to not animate to negative values (r273001)
• Changed blending of border-image-width to be discrete between auto values and other types (r273635)
• Fixed border-image-outset to handle float values (r273478)
• Fixed border-image-slice blending to account for the fill keyword (r273625)

CSS

• Changed min-content and max-content keywords to behave as an initial value in block axis (r273206)
• Changed CSS grid to not allow negative heights (r273470)
• Fixed min- and max- widths of grid affected by ancestor (r273435)
• Changed the initial value for border-image-outset to 0 (r273882)
• Implemented :focus-visible (r273812, r272983)
• Implemented the first case in Definite and Indefinite Sizes specifications in section 9.8 for flexbox (r273072)
• Fixed runtime-disabled CSS features still appearing enabled via CSS.supports() (r273385)
• Removed support in the CSS parser for -khtml- prefixed CSS values (r273637)
• Removed support for pos and pixel prefixed CSS values (r273627)

CSS Color

• Added experimental support for CSS Color 5 color-contrast() (r273683)
• Added experimental support for CSS Color 5 color-mix() (r273244)
• Added experimental support for CSS Color 5 Relative Color Syntax (r273127)
• Changed color(lab ...) to serialize as color(lab ...) not lab() according to latest CSS Color 4 spec (r273211)
• Fixed lab() and lch() colors to clamp out-of-bound values at parse time (r272909)
• Fixed lch() colors to serialize as lch() (r273078)

CSS Aspect Ratio

• Added support for aspect-ratio on flexbox items (r273193)
• Changed an aspect-ratio that ends with forward slash to be treated as invalid (r273068)
• Fixed aspect-ratio showing in computed styles when disabled (r273314)
• Changed to take box-sizing into account in replaced element intrinsic sizing for aspect-ratio (r273753)

JavaScript

• Enabled private methods (r273125)
• Implemented private static methods (r273107)
• Implemented top-level-await (r273225)
• Implemented RegExp Match Indices (r273086)
• Implemented GC verifier (r273138)
• Added support for modules in Workers and Worklets (r273203)
• Added support for modules in Service Workers (r273224)
• Avoided performing toObject for options in new Intl constructors to align them to a new spec change (r273153)
• Reduced promise reaction memory usage when there are multiple reactions (r273718)
• Optimized object-reset expression (r273135)
• Optimized Promise#then by avoiding function allocations in major case (r273605)
• Micro-optimized for-in (r273766)
• Threw TypeError when getFunctionRealm hits revoked Proxy (r273661)
• Threw TypeError when TypedArray’s [[DefineOwnProperty]] failed (r273750)
• Fixed delete with index for module namespace object when arbitrary module identifiers use index (r273816)

WebAssembly

• Extended wasm type with type index (r273813)
• Implemented non-trapping float to int conversion (r272933)

Web API

• Enabled Paint Timing (r273221, r273220)
• Changed window proxy of detached iframe doesn’t respect updates to global values (r273901)
• Fixed devicemotion and deviceorientation events to work in third-party iframes with Feature-Policy allowing it (r273444)

Media

• Fixed media segment getting incorrectly dropped when using negative timestampOffset or when source buffer appendWindow is set in MSE (r273461)
• Fixed audio that stops playing when backgrounding a page that is playing and capturing audio (r273069)

WebRTC

• Added support for WebRTC priority (r273550)
• Fixed MediaRecorder.stop() to work correctly when recording has been paused (r272911)
• Added support for BigInt as media-stream encryption key (r273158)

Accessibility

• Added the ability for an embedded accessibility image description in an image file to be reported if available (r273214)
• Fixed VoiceOver announces grid as having “0 columns” causing VoiceOver to not enter the grid (r273715)
• Fixed VoiceOver incorrectly announcing groups in ARIA tree instances as empty (r273328)

Scrolling

• Fixed scroll snapping when dragging scrollbars (r273690)