The issue is setting .preferredColorScheme on the sheet. A nil value (for system appearance) does nothing. A full working solution without using UIKit can be found here: https://gist.github.com/chockenberry/a2a23a12604e333b1c2a8b71e7a24155 Apple folks: FB15105356

The new technique is to enable an inspectable property on the JSContext and WKWebView. https://webkit.org/blog/13936/enabling-the-inspection-of-web-content-in-apps/ -ch

@BenjaminApple There are three primary use cases for most macOS developers running a beta OS in a virtual machine (such as macOS Ventura in UTM): To download their existing apps from the Mac App Store to verify that everything works correctly on the new OS. An Apple ID is needed to download from the Mac App Store. To build and debug their apps using Xcode. An Apple ID is needed to setup an account in Xcode so automatic code signing can be used. To test apps that use iCloud. An Apple ID is needed to access iCloud in System Settings. -ch