Release Notes for Safari Technology Preview 80

Safari Technology Preview Release 80 is now available for download for macOS Mojave and macOS High Sierra. If you already have Safari Technology Preview installed, you can update in the Software Update pane of System Preferences on macOS Mojave and from the Mac App Store’s Updates tab on macOS High Sierra. After updating to macOS Mojave, you may have to reinstall Safari Technology Preview.

This release covers WebKit revisions 243538-244110.


  • Updated setBlendColor, setViewport, setScissorRect in GPURenderPassEncoder (r244093)
  • Replaced unsigned longs in WebGPU with uint64_t (r243658)
  • Standardized WebGPU object reference counting and creation logic (r243563)
  • Removed WebMetal experimental feature in favor of WebGPU (r243666)


  • Implemented ResizeObserver (r243643)
  • Added support for “noreferrer” window feature to (r243705)
  • Added support for <object>.contentWindow (r243638)
  • Changed window.closed to true immediately when close() is invoked (r243661)
  • Changed to close the service worker database on network process suspension (r244097)
  • Changed Fetch to allow used body replacement in Request constructor (r243757)
  • Fixed HTML fragment serialization to not strip whitespace from URL attribute values (r243821)
  • Made someWindow.frames, someWindow.self, someWindow.window always return someWindow, even without a browsing context (r243669)
  • Removed conditional parsing of <noembed> content in the HTML parser (r243782)
  • Fixed the loadstart event for XMLHttpRequestUpload to be correctly initialized (r243765)
  • Fixed getBoundingClientRect returning an empty rect on a collapsed range (r243635)
  • Fixed the select element not showing a popup if the element lost focus while the popup was previously shown (r243601)
  • Pasting a table from Confluence strips table cell content (r243653)
  • Updated to ensure resetting the storage quota takes into account third party origins (r243806)

SVG Animation

  • Fixed SVG Animation (SMIL) on <text> or <tspan> to work correctly on the second run (r243780)


  • Added support for muting screen capture and camera/microphone independently (r243899)


  • Implemented white-space: break-spaces value (r244036)
  • Removed functionality for -apple-trailing-word (r243819)
  • Allowed FontFace names which start with a number (r243637)


  • Prevented <svg> elements with labels and no accessible contents from getting exposed as empty AXGroups (r244029)
  • Changed to automatically compute accessibility labels for Apple Pay buttons (r244061)

Web Inspector

  • Added support for showing WebGPU contexts in the Canvas Tab (r243763)
  • Added support for showing the resource initiator in the summary of the headers in the Network Tab (r243614)
  • Adjusted the energy impact thresholds in the CPU Usage Timeline (r243704)
  • Ensured that the Script Profiler debugging thread is not counted as part of the page usage in the CPU Usage Timeline (r243679)
  • Disabling a breakpoint for a specific event listener no longer removes it from the list of breakpoints (r243722)
  • Prevented breakpoints for attribute modifications from firing when breakpoints are disabled (r243719)
  • Prevented single clicks from following links in text editors that are not read-only (r243826)

Safari Extensions

  • Legacy Safari Extensions (.safariextz files) are no longer supported. Safari App Extensions and Content Blockers, which can take advantage of powerful native APIs and frameworks as well as web technologies, can be distributed with apps in the App Store or from developers’ websites. You can learn more at