Hi,
Push notifications are connected to the messages system in Moodle (in your profile settings, you can configure how you want to receive messages from Moodle)
As far as I remember, there are a couple of messages send by the Feedback module (feedback notifications and feedback remember) if the user configure to receive that type of notifications to their mobile device he will receive it
But I think that those notifications are send only for the teacher when someone ask a feedback
Regards