It's a media server that lets you access movies/tv shows/music from other devices via apps or a web interface. In this post's case it's talking about the Jellyfin app on Roku that lets you watch/listen to stuff through Roku devices.

In my experience it's been pretty nice and easy to use, and the Roku app's decent enough for what I'm after, which is simply watching stuff from my PC on other tvs in other rooms.

Edit:
Btw here's a link to the post OP screencapped: https://social.linux.pizza/@tgpo/111551351394147888

[–] [email protected] 6 points 11 months ago

That's me 😀

I like to post video demos of new features I'm working on, so if anyone wants to see previews of what's down the pipeline, check it out.

https://social.linux.pizza/@tgpo