If a developer downloads the app, they can verify it. But more to the point, I published an app on the Play Store that actually verified its own signatures (as

If a developer downloads the app, they can verify it. But more to the point, I published an app on the Play Store that actually verified its own signatures (as an anti-piracy measure) and it worked correctly. Not only that, but it used the signature as a key to decrypt some of the assets, so a changed signature would mean the app would completely fail to work. So it's a solvable problem on Android. But not at all on other ecosystems.