parent comment was edited, originally said "i thought they [Tailscale] hated that thing [Headscale]"
they literally have on their website that they encourage people to use Headscale if they want an open source solution for the coordination server or just to learn how the internals work, they coordinate with Headscale maintainers to avoid breakages, and they don't discourage (but also don't require) employees contributing to Headscale
that was me! then i realized in the apps (except iOS?) they allow you to specify your own coordinator server... so if they hated them then they'd never build that in! so i removed that part of my comment before it had any replies that I was aware of
edit: see comment below me; iOS now has that ability!
ah! very cool. thanks for the context :). I must have missed the shoutout on the website. It's cool that they coordinate with headscale to avoid breakages as well