> Tangentially, on Android every app you have run at least once can know your phone number through standard APIs. How would that work? As far as I'm aware an a

> Tangentially, on Android every app you have run at least once can know your phone number through standard APIs. How would that work? As far as I'm aware an app either needs explicit permissions (READ_PHONE_STATE) or the user gets prompted when the app requests the phone number (as shown in https://android-developers.googleblog.com/2017/10/effective-phone-number-verification.html https://android-developers.googleblog.com/2017/10/effective-...).