Relays can federate. The point is that Nostr as a protocol is saying nothing about this and does not care either.
I'm running an indexer (a relay) which federates with other relay indexers. Similar how activitypub relays work. Any client can connect to indexer to help bootstrapping and find metadata around events. There are many ways to discover stuff from clients even without being connected to the same relay.
I'm running an indexer (a relay) which federates with other relay indexers. Similar how activitypub relays work. Any client can connect to indexer to help bootstrapping and find metadata around events. There are many ways to discover stuff from clients even without being connected to the same relay.