Left 4 Dead 3 leak

Punching Beta: "With The International of Dota 2 occurring this week in Seattle, some of the players were invited to Valve’s headquarters for a tour. Being on top of their game, some of these keen eyed players spotted a reference to Left 4 Dead 3 in an on-screen changelog during the tour. See the 4th line down. Is this Left 4 Dead 3 leak for real?"