It's lik an old wound that won't fully heal before someone tears it open again. Here's another batch of Half-Life 3 rumors. This time it is a Portal VR demo for the upcoming HTC Vive that has been revealed to have several mentions of both Half-Life 3 and Left 4 Dead 3 in the programming code. Some of which is old, but also newer stuff like a crowbar zipline and a spy grenade from the former game and texture sets for two elderly men in the latter game.
Although we really shouldn't be poking in this and get anyone's hopes up, it is always good to have some sort of indication that Valve may still be working on something Half-Life related in between all the Dota and VR stuff.
Thanks, GamesRadar.