@andrearivolta_xyz @Tutanota Few potential ways on how to do this would be storing what you'd normally track when online into a file and then sending that file to Meta servers once the device is connected.

(That is a possibility, can't confirm whether they're doing this but it is most likely.)

As for offline activity as in not on device, the device has microphone, sensors, gps, etc. so those are abused not just by Meta.