We're developing a web app and want to add "Sign in with Apple" functionality. We don’t have a native iOS app, but it looks like a native app bundle ID (Primary App ID) is required for configuration. Does this app need to be published on the App Store, or can we create a "dummy" app and use its ID as the Primary App ID? We only need the web experience and don’t plan to build a native app.

During authentication flow in Safari, we have a case when in order to satisfy a condition policy, user needs to install the app on his device. Depending on the OS, we ask him to install different applications. Since on iPadOS User Agent in Safari is same as on MacOS Catalina, what is recommened way to distinguish OS on server side?iPadOS:Safari: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0 Safari/605.1.15MacOS Catalina:Safari: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36