Release Notes for Safari Technology Preview 107

Safari Technology Preview Release 107 is now available for download for macOS Catalina and macOS Mojave. If you already have Safari Technology Preview installed, you can update in the Software Update pane of System Preferences on macOS.

This release covers WebKit revisions 261057-262002.

Web Inspector

  • Network
    • Adjusted the spacing of the navigation items so that none are hidden when previewing a resource (r261497)
  • Sources
    • Added showing the name of the Worker if it exists as the title of its main resource (r261104)
    • Fixed source mapping issue when combining single-child directory chains (r261200)
    • Fixed restoring global DOM, URL, or event breakpoints incorrectly enabling all breakpoints (r261340)
    • Supported CSS pretty printing when a url() is nested inside a url() (r261772)
  • Timelines
    • Fixed the memory stacked area graph to not extend beyond the “stopping time” marker (r261197)
  • Storage
    • Fixed double-clicking on a cookie field to start editing that cookie (r261339)
  • Layers
    • Ensured that the text at the bottom of the details sidebar doesn’t overlap (r261237)
  • Console
    • Added showing EventTarget listeners as an internal property (r261670)
    • Added showing Worker name as an internal property (r261499)
  • Miscellaneous
    • Accessibility
      • Fixed Left/Right arrow keys to collapse/expand details sections (r261962)
    • Remote Inspection
      • Provided a way to turn on or off ITP debug mode and AdClickAttribution debug mode (r261103)
      • Dropped support for iOS 8.x, iOS 9.x, and iOS 10.x (r261108, r261109, r261105)


  • Changed the initial value of transform-box to be view-box to fix some SVG animations (r261752)
  • Fixed computing the correct perspective matrix on a box with borders and overflow: hidden (r261619)
  • Fixed Object.prototype.toString to match standards (r261159)
  • XML external entity resources should only be loaded from XML MIME types (r261443)


  • Changed the cursor to update during the rendering steps, rather than on a 20ms timer (r261741)
  • Fixed the computed min-width and min-height for auto depending on the box (r261974)
  • Fixed disappearing content with CSS parallax on an overflow scroll (r261837)


  • Fixed repaint issues when the login field collapses on (r261979)
  • Fixed text clipped when rendered with fonts which have a negative line gap metric (r261573)
  • Fixed table sizing when max-width is used (r261924)


  • Fixed tapping on the trackpad in a <select> to flash the scrollers (r261368)
  • Fixed a <select> that sometimes becomes non-scrollable (r261427)
  • Fixed overflow scrollbars not growing when hovered (r261132)
  • Fixed find not always scrolling search results into view (r261819)
  • Fixed composited scrolling interfering with the propagation of perspective (r261632)
  • Fixed scrollbars flickering in RTL scrollable regions (r261535)


  • Changed to ignore a poster set after playback begins (r261341, r261576)
  • Fixed media controls tracks menu showing “Auto” selected instead of the track selected via the JavaScript API (r261084)


  • Improved the accuracy of IndexedDB estimated write size computation (r261533)
  • Fixed a bug that could cause IndexedDB log files to grow without bound (r261533)


  • Implemented Intl.Locale (r261215)
  • Implemented BigInt.asIntN and BigInt.asUintN (r261156, r261199)
  • Enabled logical assignment operators (r261728)
  • Ensured IntlCollator.prototype.resolvedOptions returns relevant locale extension keys in alphabetical order (r261182)

Web Animations

  • Fixed the animation engine to not wake up every tick for steps() timing functions (r261926)
  • Fixed animations with a single keyframe not getting accelerated (r261756)
  • Fixed calling reverse() on an accelerated animation having no effect (r261637)
  • Coordinated “update animations and send events” procedure across multiple timelines (r261218)
  • Fixed Document.getAnimations() to only consider document connection and not timeline association (r261488)
  • Fixed the animation of font-size using rem values (r261861)

Async Clipboard API

  • Enabled clipboard API access when pasting from a menu item or key binding (r261825)
  • Fixed cut and paste from Google Doc to Notes in several (non-Latin) languages (r261247)
  • Preserved character set information when writing to the pasteboard when copying rich text (r261395)


  • Implemented accessibility of HTML 5.1 Drag & Drop (r261248)

CSS Grid

  • Cleared the override width for computing percent margins (r261841)
  • Changed to treat percentages as auto for the minimum contribution (r261767)
  • Fixed auto repeat with multiple tracks and gutters (r261949)

Bug Fixes

  • Added quirk for cookie blocking latch mode redirecting to under (r261724)
  • Changed to enforce a URL cannot have a username, password, or port if its host is null (r261173)
  • Changed XML external entities to require an XML MIME type to be loaded (r261451)
  • Fixed the playhead in Touch Bar continuing when loading stalls (r261342)
  • Fixed the search field on clipping the submit button (r261450)
  • Fixed setting a host on a URL when no port is specified (r261212)
  • Limited the HTTP referer to 4KB (r261402)