Here's what worked for me in the end after comparing to what Xcode generates for app icons in the asset catalog. The iPad variant seems to be necessary for it to work there. Hopefully Apple fixes Xcode in a future beta,

Not working for me in beta 2

Xcode also warns about the reverse error, a parameter in the method declaration that's not documented

I like how building DocC with Xcode 16 now warns about documented parameters that don't exist in the method declaration #Xcode #iOSDev

I’m pretty sure this is the Swift compiler telling me I need to upgrade my M1 mac mini? #SwiftLang

Swift 6 deprecates UIApplicationMain, replace it with main to silence the error #iOSDev #SwiftLang