L4D3 And Source 2 Engine 2 Vaguely Spied Upon
So, "Squads" mode wasn't the last bottom of the barrel news. Apparently, some DOTA2 Redditors got to tour Valve's offices and they repaid their kindness with taking pictures of stuff and then scouring them for hints about Gaben's secret pie collection. They found something else, the ingrates: some...task screen (see above) has vague mentions of Source 2 engine (Source was the engine that ran most of the games - and a pixelated turd called EYE - since Half Life 2 was released almost an Iraq war ago) and Left 4 Dead 3 (see below).
Again, baseless speculation abound, but if you're a zombie fan/poor game maker, this might be your day!