Release Notes for Safari Technology Preview 165

Safari Technology Preview Release 165 is now available for download for macOS Monterey 12.3 or later and macOS Ventura. If you already have Safari Technology Preview installed, you can update it in the Software Update pane of System Preferences on macOS Monterey, or System Settings under General → Software Update on macOS Ventura.

This release includes WebKit changes between: 260164@main…260848@main.

Web Inspector

  • Added support for color-mix CSS values in the Styles details sidebar of the Elements tab (260332@main)
  • Added setting to always show rulers when highlighting elements (260416@main)


  • Added support for text-transform: full-size-kana (260307@main)
  • Added support for margin-trim for floats in block containers that contain only block boxes (260318@main)
  • Added support for x units in calc() function (260678@main)
  • Added support to image-set() for resolution and type as optional arguments (260796@main)
  • Fixed preserve-3d not being applied to pseudo elements. (260324@main)
  • Fixed opacity not applying to dialog element ::backdrop pseudo-class (260556@main)
  • Fixed the background to not propagate when content: paint is set on the body or root element (260766@main)
  • Fixed table-layout: fixed not being applied when width is max-content (260501@main)
  • Fixed font-optical-sizing: auto having no effect (260447@main)



  • Fixed accounting of margins in multi-column layout before forced breaks (260510@main)
  • Fixed floats with clear to not be placed incorrectly (260674@main)


  • Fixed SourceBuffer.timestampOffset not behaving correctly with webm content (260822@main)
  • Fixed HDR data to no longer be clipped in AVIF images (260512@main)


  • Fixed resetting the value of an input type=file to null to make the input invalid (260688@main)
  • Fixed minlength/maxlength attributes to rely on code units instead of grapheme clusters (260838@main)

Web Animations

  • Added support for the length property of CSSKeyframesRule (260400@main)
  • Changed animation of mask-image to be discrete (260756@main)
  • Fixed custom properties not being treated as valid in the shorthand animation property (260759@main)
  • Fixed transition-property: all not applying to custom properties (260384@main)


  • Fixed Secure Curves not having a namedCurve property (260599@main)


  • Fixed restored WebGL context not being visible until layout (260693@main)


  • Fixed lazily loaded frames to get a contentWindow/contentDocument as soon as they get inserted into the document (260713@main)
  • Fixed frames to not be lazily loaded if they have an invalid or about:blank URL (260612@main)



  • Fixed aria-errormessage to not be exposed when aria-invalid is false (260545@main)
  • Fixed text associated with various types of elements not being exposed (260521@main)
  • Fixed invalid summary elements to not be exposed as interactive (260546@main)
  • Fixed some inputs not being treated as invalid despite being rendered as such (260544@main)

Web Extensions

  • Fixed Content Blocker API ignoring some CSS selectors with uppercase letters (260638@main)