Release Notes for Safari Technology Preview 176

Learn about the latest web technology updates in Safari Technology Preview: CSS, Rendering, Accessibility, Media, and Web API.


Safari Technology Preview Release 176 is now available for download for macOS Sonoma beta and macOS Ventura. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update.

This release includes WebKit changes between: 266088@main…266418@main.


  • Added support for contain-intrinsic-size: inherit (266100@main)
  • Implemented linear(...) timing function for CSS animations & transitions (266195@main)
  • Fixed auto none support for contain-intrinsic-size (266136@main)
  • Fixed computing <hr> width attribute set to 0 or 0px (266418@main)


  • Fixed out-of-flow boxes not showing (266366@main)
  • Fixed canvas not showing the results of CanvasRenderingContext2D.putImageData until a forced re-render (266397@main)
  • Fixed scrollbar not updating on CSS color-scheme change (266176@main)
  • Prevented invalidating columns when the entire table is being destroyed (266344@main)


  • Fixed display: contents elements sometimes missing their children (266407@main)
  • Fixed incorrect accessible name from multiple <label> elements (266151@main)
  • Fixed unexpected speech synthesis behavior for unordered lists (266383@main)


  • Implemented automatic text track selection for 'metadata' tracks (266380@main)
  • Fixed RTCRtpSender maxFramerate encoding parameter having no effect (266128@main)
  • Fixed updating time stamps on media controls to update while scrubbing the timeline (266339@main)


  • Added support for the title attribute for pattern validation errors (266311@main)
  • Aligned naturalWidth and naturalHeight with spec, changing from int to unsigned (266302@main)
  • Changed to return opaque origin for blob: URL containing inner non-http(s): URL (266247@main)
  • Converted embed hidden into a proper boolean attribute (266399@main)
  • Throttled mousemove events to one per rendering update (266341@main)
  • Fixed ElementInternals.setFormValue(<nullish value>) to clear the submission value (266126@main)
  • Fixed custom highlight logic for checking author and set text color (266117@main)
  • Fixed custom highlight text decoration to respect priority (266184@main)
  • Fixed emoji characters sometimes getting incorrectly drawn in text style (266089@main)
  • Fixed URL pathname and search setter incorrectly stripping trailing spaces (266252@main)
  • Handled focusability for plugin elements which have browsing context (266286@main)