Sort of #screenshotsunday (photo instead) browsing mastodon and chatting on the tildeverse IRC this evening.
It's a 2017 iMac running a completely free software Linux distro, #trisquel 9, with no non-free firmware blobs etc. Tried this a while back, as I like to see what's possible with 100% free software each year, and this is actually very pleasant so it has stuck.
I actually contributed a tiny little bit toward the then in-preparation #trisquel 9 a year or so ago. I left using trisquel for various reasons, but it's fun to come back to it knowing I helped out in a very small way.
It's essentially Ubuntu with non-free stuff and snaps removed, plus a customized default MATE desktop.
It lags behind... the recent Trisquel 9 is from Ubuntu 18.04. However Ubuntu 18.04 is still quite a nice sweet spot of being stable, boring, and running most what you want.
A single-family instance of Mastodon.