Still waiting on someone to 'find' code for Half-Life 3... This is interesting though. Most of the time it's small references like this in code that can hint at something big. Look at Call of Duty: Black Ops 2, Treyarch made the mistake of putting the name of their second DLC in the code of their website (
Found here in image form) that was later actually released. So maybe this does say something... I mean, Valve isn't perfect, they do slip up. They seemed pretty quick to lay the ban hammer down on the person that first reported it.
Either way, thanks for sharing, really interesting.