New Valve leak may confirm Left 4 Dead 3 and Source 2 engine are in development
 

Recently a DotA 2 player took a photo of an on-screen changelong while on a tour of Valve's offices and leaked it onto the net. The internal changelog mentions Left 4 Dead 3 as well as Source 2, all but confirming their status as current Valve projects.

http://vr-zone.com/articles/new-valv...in-development