Blocked newly installed app

[iulko]

While doing no new install or anything like that I got an notification that Rethink blocked newly installed app: 0

What would the 0 be?

[ignoramous]

It is Android itself.

A notification means that's the first time Rethink is "seeing" it make connections.

As you may guess, Android cannot be installed / uninstalled... but yeah, that's how Rethink treats such "apps" that aren't really apps but appear to it as so.

Generally speaking, the Android OS assigns ownership of outgoing connections to itself, erroneously sometimes. For example, I find the OS often attribute outgoing connections from Firefox to itself aka user 0 aka Android.