How does the application know what was already on the device (Android)?

Question

Android

There is an application that provides the execution of a certain number of tasks on the device! So the question is, how does this very application find out what has already been installed on this device? I did a Reset of the phone, then tied it to another account, then downloaded this application, but it still writes what was already on this device. (Advert App)

Answer 1

It is highly doubtful that this program would receive IMEI / MAC-and at the system level, most likely it accesses the standard API. Therefore, look towards Xposed Framework + XPrivacy
It is possible to replace the identifiers given to the program, but there are nuances, the solution is not universal.

Answer 2

IMEI, MAC WI-FI or Bluetooth