> IIRC it got replaced at some point. The current iteration of Source's netcode doesn't have anything to do with that, though.
Do you have a source (heh) to back that? Lots of the networking configuration cvars from 1.6 are still there in CS:GO and do the same thing. Maybe it was cleaned up but I wouldn't be surprised if it's still mostly the same code.
GameNetworkingSockets is pretty cool, and integrating it must have required some extensive changes, but it's more of a networking middleware library. I thought blattimwind was referring to the gameplay related netcode (prediction, interpolation, lag compensation, etc). My understanding is that it hasn't changed much since the 1.6 days, because all of the configuration knobs are still available today, but maybe they rewrote it and I'm just out of the loop. It'd be a major task to do that without affecting gameplay "feel", which is why I was interested in some source to read more about it.
Those are GC (Game Coordinator, server list, matchmaking) and Steam (items, trading, etc) protobufs, not for the actual netcode of Source games. There also seems to be some demo (saved game replays) related messages there, but I don't see anything gameplay related.