The task of the project was about finding an obfuscated app on the play store, modifying it such that it would notify another app whenever it was opened.
I did not really have a quick way to check wheter an app on the play store was obfuscated or not, so I decided to choose an app that I knew for sure had at least some kind of obfuscation, and that app is Whatsapp Messenger.
The apk for "Whatsapp Messenger" I got is version 2.20.123, x86 architecture (because that's the architecture of the emulator I am currently running)