It is open source but you can’t publish modified code (this is to ensure there will be no malicious forks like there was with newpipe)

plus you missed the entire point:

… app for watching online video content - not just youtube, but nebula, peertube, twitch and more.

It’s an app that allows you to watch the same creators across many platforms

A perfect 89° angle

NewPipe

And after the 1st of July too, probably