Left 4 Dead 3 With Source 2 Leaked During Valve Tour [Update]

A few lucky Reddit members from the Dota 2 sub-Reddit forum were invited to Valve recently , who were allowed to take some photographs during their visit. You can check out the photo album here. However, there is one photo in particular that is of great significance as it reveals an unannounced game being built on an unannounced game engine. 

This photo seems to confirm that Valve is working on Left 4 Dead 3 with Source 2. I'm sure these photos are legit, but is Valve playing tricks on us? They must have known that a group of visitors were coming by and were going to take photographs on whatever that may be of great interest.

 Do you think Valve is actualy working on Left 4 Dead 3? And is anyone else surprised that Valve can count to 3?

Update: There's also an apparent Left 4 Dead 3 site at http://l4d3.ru/, which contains a countdown to August 21, a date when Gamescom is suppose to go down in Germany. I doubt this site is legitimate though as it's hosted on a Russian domain. It was registered on June 19 and by a "private person," which appears very odd as well. Not to mention there's no accompanied ARG (Alternate Reality Game) that Valve typically creates surrounding a game announcement.

In June, ValveTime found some juicy info from a Valve project tracker, revealing multiple mailing lists for a Left 4 Dead 3, providing some credence to the photo taken from the Reddit community. On the tracker, a drop down menu reveals that there are groups for L4D3, L4D3 Audio, and L4D3 Developers, as well as several Source2 groups. Going deeper, apparently the L4D3 group contains 68 members, which would make it the third largest project at Valve.

Half-Life 3 is also in the tracker, though there's only one group listed for the project. ValveTime suggests the project is either inactive or still in its early days.