I personally wouldn't view the code as that makes you a liability for foss. If you view proprietary code you need to be very careful you do not mistakingly write similar code.
Just because the source code is available does not make it foss. It is in fact quiet proprietary even though everyone seems to think differently.
I frankly do not see the point of it. We have foss apps that work just as well or better without the baggage. What's worse is that they are unofficial for all the services so you could end up causing headaches. For instance, the Nebula viewer is not approved by Nebula and could break at any time. I realize that could be said for Newpipe and others as well but they are at least foss and flexible.