I think the `nostr:...` scheme is not actually a Uniform Resource Locator, because it doesn't tell you where the data is located. For instance if I see the string `nostr:npub1sn0wdenkukak0d9dfczzeacvhkrgz92ak56egt7vdgzn8pv2wfqqhrjdv9` I understand that this identifies a Nostr keypair but I don't know where to find data for that keypair. The scheme does fall under the definition of a Uniform Resource Identifier, or maybe even the stricter class Uniform Resource Name. But nobody talks about URNs, so maybe best to just use the less-specific term "URI" here.
mplorentzandfiatjaf_
Martin Dutraandfiatjaf_