it will save trillions of bytes of bandwidth. it is like rsync for nostr. the idea of fetching notes you already have will be an ancient concept.

this is even more important when you're pulling from multiple relays. right now you download tons of extra stuff for no reason. this fixes that. 

 Whats preventing it from being merged already? 

 think they are just working on minor details like error messages atm 

 Nice