I think he means a locally run relay to act as a unified cache for all Nostr apps so they dont need to cache the same data seperately.
Discussion
ohh that has to be a very lightweight implementation of a Relay
It would enable clients to be lighter weight. Like middleware in between your relays and clients. Or kinda like a push notification system that knows what you’ve already seen maybe
yeah I seeing more a proxy server that acts as a push notification server and cache for clients that actually having the relay on the phone.