We've all seen posts about starting services automatically in Android which mostly doesn't work. WhatsApp gets this done every morning. I assume they don't send billions of fcm messages to all devices to wake them up and do a backup. Does anyone know how they do it? Or are they privileged?
Another one: My GF got a new phone and WhatsApp did not ask for any permissions (at least I did not see it) to do a backup on Google Drive. Ususally oAuth has to be used to do so (and has to be confirmed via browser). Maybe Google backed up all of the apps (accounts?) but are they really able to restore permissions/credentials on a new phone (or token?). For sure she wasn't asked for any permission regarding the backup except the login to her Google account when the phone started.
Another one: My GF got a new phone and WhatsApp did not ask for any permissions (at least I did not see it) to do a backup on Google Drive. Ususally oAuth has to be used to do so (and has to be confirmed via browser). Maybe Google backed up all of the apps (accounts?) but are they really able to restore permissions/credentials on a new phone (or token?). For sure she wasn't asked for any permission regarding the backup except the login to her Google account when the phone started.