It lets me stream my media from my owner server to my own devices, I like
Discussion
but unfortunately it‘s not open source and for some stuff you need an account on plex.tv
Jellyfin is a decent open source alternative to Plex... No web browser access, but their is a desktop and mobile application for Jellyfin that both work solid imo. I think the biggest advantage Plex has over Jellyfin, besides the online browser access, is a bit more of a polished UI/UX... otherwise Jellyfin has been a great open source alternative.