So school shut be 18+ as well then? The best teacher is the Internet for just about anything. If it is info about how to garden or how to setup networking gear. The internet has it.

How would you verify it though? Someone could abuse it it and report anything for CSAM. Verifying is kind of a difficult thing in this case.

may kill a background app even when told not to

Most of the time this can disabled somewhere in the app permissions. i have done this for a couple of apps without much issue.

google firebase notification system

Why though? If a app has its own implementation this is a non issue really.

Normally yes. But they also have mailbox application that kind of acts as a message queue both ways

Their is briar. It is fully decentralized and works p2p over for.