Joshua:
For me personally, it was just time for a change. I simply could no longer provide the effort (mental or time-wise) that the role demanded, and thus I was not performing my duties to an acceptable degree, facing severe burnout, and risks to my mental health. It was time to step aside. Hand-off is ongoing and is amicable, and there is good communication lines, so there is little to no risk of a hostile fork or anything of that nature. Jellyfin will continue for a long time to come, just not with me at its head.
When I started Jellyfin, I thought it would be something used by a few hundred, or maybe if we were lucky, a few thousand, users. We might put a few pet features in, and do a bit of cleanup, but really, I didn't expect much. Now here we are 7-and-a-half years later, and it's the #1 FLOSS media server, a truly viable alternative to Plex for literally millions of server administrators and probably 10x that many individual users, and we've left our parent project completely in our dust. We've proven that FLOSS works, and is in demand.
I truly hope Jellyfin outlives me, and I trust those in the team to keep the philosophy and code alive.
For the last time, happy watching all!
Anthony:
My particular reasons are a bit different, so I figured I would post as well.
For myself, though I don't touch much code these days, I do a lot to manage things in the backend and with App Stores/etc. After 7.5 - nearly 8 - years, it's been a long time since I've been able to give much of my free time to Jellyfin. My life is changing and I've got other things that must take priority.
I am fully committed to a smooth transition, which is something I've wanted for a long time anyway. Even if the transition takes a year, I'm still down to do that. I want Jellyfin to succeed, and it should.