@grote @y20k This issue can be addressed in several different ways depending how the app was published on F-Droid.
For apps published with the explicit consent from the maintainer: F-Droid can ask the maintainer to include an `adi-registration.properties` with the maintainer's own unique key if the developer has an account with Android developer verification program. Otherwise, they can ask the maintainer to use F-Droid's own key and let F-Droid claim the package ID instead.
If the developer doesn't care, inactive, or no explicit consent has been given, F-Droid can claim it using an skeleton package (https://github.com/android/security-samples/tree/main/AndroidDeveloperVerificationAPKSigningExample) for verification. But this can be complicated depending on the package ID. If F-Droid uses a different package ID, it should be easy. If not, F-Droid needs to ask Google to explicitly allow them to use the same package ID since Google wants to reduce collision as much as possible.