Thank you for the report. I filed https://bugs.webkit.org/show_bug.cgi?id=266871 to track this issue. Safari Technology Preview Release 185 contains an early developer preview of WebGPU and most, but not all, of the standard functions are implemented. The unpack4x8unorm function will be added to a future release of Safari Technology Preview.

Hi @pacera, WebGPU is available as an early preview for testing in iOS 17.4, similar to the way it is supported on Safari Technology Preview. It can be enabled via Safari's Settings -> Advanced -> WebKit Feature Flags in the Settings app. Please note, the implementation in iOS 17.4 is an early preview and targeted towards website developers. It is not fully functional and that is why it is disabled by default.

@saalisumer_microsoft these feature flags only impact Safari and not WebKit generally. For WKWebView, the feature will work when its enabled by default. Can you please try on the iOS 26 beta? WebGPU is enabled by default there.