Plex Media Server is the backend for the Plex media system.

Plex's frontend media player, Plex Home Theater, is Windows/Mac only;
however, you can stream your local files on Linux from your web
browser. Plex Home Theater allows the user to manage and play video,
photos, music, and podcasts from a local or remote computer running
Plex Media Server.

Plex Media Server runs as plex:plex (UID/GID 279) with its $HOME as
/var/lib/plexmediaserver:

# groupadd -g 279 plex
# useradd -u 279 -d /var/lib/plexmediaserver -s /bin/false -g plex plex

After installing, grab an account from https://www.plex.tv and visit
http://localhost:32400/web  configure your server.