If there's one thing you can rely on in 2016, it's this: if Valve release a sheet of code, people will pillage it for Half-Life 3 references. Valve recently rolled out the SteamVR Performance Test, which is designed to establish how fit a PC is for VR. Predictably enough, the community at Valve Time has stripped the program down and discovered a bunch of secrets inside.
Among the interesting tidbits are a collection of images which appear to be an updated version of the Dog character from Half-Life 2. The same model has circulated online for a while, but the Performance Test has several new ones hidden in its files, one of which you can see below:
It's hardly evidence that Half-Life 3 is confirmed: as the source at Valve Time notes, the image could simply be a 3D sample model for a toy statue (the model's creator, Tristan Reidford, also collaborated on a toy version of the gravity gun).
There's a bunch of other stuff in the files, most of which are half-finished VR demos using assets from Half-Life 2, Portal and Dota 2, among others. There is some evidence pointing to Left 4 Dead 3, though. In a directory marked "L4D3", textures for a character called 'Retired Engineer' were found. The textures don't reveal much more, unfortunately, and nor do other character textures that don't appear to belong to any specific Valve series.
It shouldn't come as a surprise that elements from Valve's past games have appeared in their VR software: programmer Jeep Barnett told Kotaku last year that the company often repurposed old assets to use in their demos. Still, some will find it reassuring that brand new assets related to Half-Life 3 and Left 4 Dead 3 are out there.
Go and have a look at the full archive, which includes an aborted virtual tour of Valve's Washington offices, a surreal cockpit demo and, um, whatever the heck this is: