I think it's interesting that all recent contributions to this "open source alternative" are done by a tailscale employee. Wonder what's preventing them from making the official client open-source
(Yes the company _could_ do a sudden 180 and start intentionally breaking compatibility and forbidding that their clients be used with third-party servers - but the risk of that doesn’t seem much different than the risk of an open-source alternative being abandoned)
Probably having a full time job that people will actually support? Open source software doesn't reward effort.
Headscale does not have a nice UI, its basically all CLI usage. There's very good reason to use Tailscale for companies and there's also good reasons for Tailscale to support an opensource implementation of their control server, I've seen it from both ends as people go either way, it's a symbiotic relationship and probably one of the best examples in open source today.