The Xcode 16.0.0 Beta 4 image has been released and can be selected as follows:
macos:
xcode: 16.0.0
Xcode 16 Beta 4 Release Notes | Apple Developer Documentation
Apple Silicon VM Image Info
Xcode 16.0 Beta 4 Build version 16A5211f is installed at /Applications/Xcode-16.app
The full manifest of installed software can be found here