An enterprising developer discovered the reference to the game on site but he was quickly banned for the hack. According to him, “there were lots of interesting things I found. L4D3 was the most interesting although it hasn’t been updated in months so it may be dead.”
Is Valve trying to hide this leak, or, in fact, is this actually a dead project?
Another interesting point is that the game could use the engine “Source 2″, which is rumored to be Half Life 3’s engine.
The company has stated they won’t be showing anything at E3 2013, so I guess we’ll have to wait even more to know the truth about all of this.