This happened before and is related to how obj-c symbols are imported in Swift, not deprecation/removal of API. corners at least exists in the non-simulator SDK, so you can perhaps work-around using #if !targetEnvironment(simulator).

Isn't this the one where you have to remove the IDESourceControlKnownSSHHostsDefaultsKey key from ~/Library/Preferences/com.apple.dt.Xcode.plist ? IIRC I had to do this after upgrading to 13.x. https://forums.swift.org/t/according-to-xcode-the-identity-of-a-repository-hosted-on-github-com-has-changed/53560/6

@misacek the author of the async method, i.e. you, determines where the method is run, for instance by adding the @MainActor attribute. The caller, i.e. NotificationCenter, can't force the method to run in any particular context.