A photo taken of a changelog screen during a tour of the Valve offices has some interesting information regarding what’s being worked on.
The photo (seen on this page, courtesy of Reddit, with an expanded version here courtesy of NeoGAF and CyborgMatt) has a whole host of interesting bits and bobs, including explicit mentions of Source 2 and Left 4 Dead 3, as well as some bits and bobs about a new Dota 2 quest.
The relevant entries include “[Source 2] Restored L4D3’s devtest unit test. Ran locally 6 times without an assert” and one with a Dota 2 mark that looks like it reads “Added quest to teach player values like gold, level, last hits, or denies, and converted existing tutorials…”
So… Left 4 Dead 3 in the works? Source 2 coming along nicely? Yet more Dota 2 stuff in the works? Interesting. No mention of Half-Life 3 (of course), but I honestly wouldn’t be surprised if that’s being worked on alongside Left 4 Dead 3. In terms of pure speculation, perhaps Source 2 will launch with both Half-Life 3 and Left 4 Dead 3 as showcases. Or maybe Half-Life 3 will just never happen. This is Valve, after all.
This could theoretically be an elaborate fake, and with Valve’s typical policies everything being worked on here might be scrapped within a month, but it’s still worth some attention.