Sort of a self-hosted Youtube work-alike for your media collection. Browse, organize, and curate your stuff. Movies, shows, music. Live TV enabled, can function as a DVR.
Client apps for Android TV, FireTV, Roku, Kodi, Xbox One, PS4, and more. Or you can watch stuff in your web browser.
REST API docs: https://api.jellyfin.org/
Official package repos for Debian and Ubuntu. In the AUR. There's even a portable version (if you have the .net core runtime handy).