SteamVR's recent performance test secretly contains several references to Source 2 games, notably Left 4 Dead 3 and Half-Life 3.
At this point, Half-Life 3 has so many "confirmed" jokes and memes that we probably wouldn't take an actual game announcement seriously. But that's not to say legitimate leaks and theories don't exist. The latest surprise example comes from this week's SteamVR Performance Test demo, which came with a Source 2 engine build. Naturally, Valve enthusiasts quickly dissected it, finding possible evidence of gameplay features for both Half-Life 3 and Left 4 Dead 3.
The first interesting detail is the SteamVR Performance Test files cites specific Source 2 directories: "left4dead3" and "hl3". That's not much itself, but breaking down the code within these files uncovers references to a possible Half-Life 3 quest system. Half-Life 3 having a quest system isn't a new rumor, but these strings do add to the body of evidence that NPCs can provide quests to Gordon Freeman during the game. Also bundled into these files? Strings detailing a "crowbar zipline" and a grenade launcher armed with "weapon_spygrenade".
Left 4 Dead 3 files weren't absent from the investigation either. Along with references to a Source 2 day-night cycle, there are hints of a new zombie type called "the nocturnal". Presumably if Left 4 Dead 3 introduces a day-night cycle, this would be a special infected enemy which only spawns once the sun goes down.
The SteamVR demo also contains texture files for two new Half-Life 3 and Left 4 Dead 3 characters, although their exact roles in the games - if any - isn't clear. On top of that, the demo seems to contain unusable Source 2 development maps referencing Aperture Science and possible space flight mechanics. That latter map is probably a reference Valve's cancelled space pirate game Stars of Blood, but at this point, it's nice to image Half-Life 3 literally shooting for the stars.
As always, nothing here is official confirmation from Valve, or in any way reflects finished Half-Life 3 or Left 4 Dead 3 products - assuming they're coming at all. All the same, wouldn't it be great to get excited for a new Valve software product that wasn't Dota 2 updates or Team Fortress 2 hats? Here's hoping at least some of this info makes its way into finished games.