specifically a feature for importers. in theory it would allow things like adding multiple URLs to multiple recordings (i.e. Spotify and Bandcamp track links). this wouldn't have to be limited to recordings tho, but I can't think of any usecases outside of that

this could be a release relationship editor-like interface, or could even be part of the relationship editor (tho it could get a bit complicated if we do so)

see also issue #37 for Harmony