Are these being used outside of NIP-29? How do people figure out where to send them if they are outside? I avoid that NIP because I don't think non-NIP-29 clients should be concerned about NIP-29 rules.
If they are supposed to stay in the relay they were received from, I think that should be added to the text.
Right now, the kind is just too generic. We might not want NIP-29 kinds scattered via the Outbox model. Or do we?