EDIT2: PeerTube is no longer using WebTorrent for Redundancy - see thread below
PeerTube has RSS feeds with WebTorrent links. You can grab those links and seed whatever content you wish using a WebTorrent client without having to install an entire PeerTube instance.
What does this do? It helps alleviate some of the streaming costs of servers and ensures a smoother experience for everyone on the decentralized web.
Yay for open source platforms!