There is also this proposal

GitHub

NIP-XX M3U Playlists over Nostr · Issue #1945 · nostr-protocol/nips

Spec: https://github.com/mp3url/mp3url/blob/gh-pages/NIP-XX.md Implementation: https://mp3url.org/?nevent=nevent1qgsdqffyfecctx6f4kyhauntadhqh5hda6...

It doesn't really need one, but there are a few things like using relative paths that isn't immediately obvious. Also with all the talk of videos on Nostr it's good to have a spec for everyone to talk about even if it doesn't get merged