Just adding https://endof10.org here for convenience.
A real-life anecdote from today on "convincing" people is that some researchers unaware that #Overleaf is on an #OpenCore model were delighted to hear about the #AGPL 'd branch - source [1] - example instance [2]. I did *not* try to convince anyone - I just pointed out the possibility and gave URLs. And a new (non-public) overleaf instance may be the result!