Topic on Engine talk:Source
Well, for the most part, they do seem rather meaningless. Though if we followed the Valve developer wiki, we'd basically list the most appropriate codebase as the "build" instead. It would allow us to categorize the various games under these main engine branches:
- Source 2004
- Source 2006
- Source 2007
- Source 2009
- Source 2013
- Left 4 Dead engine branch
- Alien Swarm engine branch
- Portal 2 engine branch
- Counter-Strike: Global Offensive engine branch
Though currently doing so does not seem to be all that important.
The speedrun guys would certainly appreciate the information. Just like "conservationists" perhaps.
Yet, except perhaps 2004-2006, 2007-2009 and 2013... yeah, it's hard to find the right granularity level.