ok, that makes sense but ultimately filters are just a query API and nothing says they cannot extend beyond simple matching if the database can do that

this will simplify your code a lot if it's just a small extension of tags instead of the whole REQ, simpler to adopt or reject, or ignore... it won't match, obviously, for relays that don't understand it, i'm not sure what that behaviour is though

that is an issue that needs to be figured out then i guess

the naive, intuitive sense of it is that filters are queries and thus they need to be more flexible than the data they relate to