OK, this is an interesting development.
From Gaming On Linux:
Valve have put up SteamVR for Linux officially in Beta form and they are keen to stress that this is a development release.
You will need to run the latest Steam Beta Client for it to work at all, so be sure to opt-in if you want to play around with it.
VR on Linux will exclusively use Vulkan, so it's going to be a pretty good push for Vulkan if VR becomes more popular. Vulkan is likely one of the pieces of the puzzle that held it back, since Vulkan itself and the drivers are still so new.
BitGamer have more detail:
While Windows gamers with sufficiently beefy systems have been enjoying the resurgence of interest in virtual reality, those on alternative platforms have largely been left out. For those watching Valve's progress in the arena, this can particularly sting: The company made much of launching its own gaming-centric operating system, SteamOS, but has thus far failed to port its own SteamVR platform - leaving those running SteamOS-based Steam Machines unable to use virtual reality functionality, until now.Valve's lack of development of, and apparent lack of interest in, SteamOS has clearly hindered its growth, and their intense focus on VR has been a source of some consternation from those who (like me) thought they should be more focused on promoting SteamOS, or on improving the Steam service itself. But it turned out that Valve have been quietly working behind the scenes to resolve some of Steam's most frustrating issues, and apparently they're also planning to promote SteamOS again... and using VR to do it, while also giving a boost to the Vulkan API in the process.
I'm not especially excited about VR, as you'll know if you've spent really any amount of time exploring the other op/ed pieces on my blog, but I did have hopes that the current trend in cross-platform game development would make Linux/SteamOS into a more viable platform for gaming... in no small part because I'd like to be able to play my favourite games in Linux, rather than having to switch to Windows 10 in three years' time. That ship seemed to have sailed, with Windows dominating OS market share numbers, and Linux developers failing to capitalize on Microsoft's PR and privacy blunders.
Today, though, it suddenly looks like Valve isn't done with SteamOS after all. And I can't help but feel like that might be a very good thing, indeed. Go get 'em, Gaben.