Even though GabeN and Co were planning to keep us in the dark a bit longer regarding the Index, their plan went awry. A premature Steam listing has been caught by a few eagle-eyed users and although Valve took down the pages, it's too late.
Note that all the info has since been confirmed by Valve, who said that the leak is accurate, although the information is "not comprehensive".
What the page revealed is that Index devices will start shipping to stores sometime in June 2019, with preorders expected already in May.
Purchasing the Index buys you the headset, integrated headphones, tether with DisplayPort 1.2 and USB 3.0 connections, power adapter, regionalised power plugs, two face gaskets (narrow and wide) and a cleaning cloth.
"Displays. Optics. Audio. Ergo. Experience the infinite virtual worlds of Valve index", the page said in the description.
If you were in doubt as to whether this is indeed a premature leak of Valve's Index, the rest of the page is proof enough - most of it is filled with placeholder text.
At the same time, Valve's Knuckles controller has been renamed to better fit the Index family and will be sold under the name Index controllers.
Valve said that they'll have more details once they've started taking preorders, so unless they manage to fumble a few more pages, we've got a month more to go.
It's difficult to estimate how Valve will do with Index based on this though, as we're yet to learn about pricing, panel size, refresh rates, etc.
For what it's worth, GabeN seems to have timed the launch pretty well, not only because of the competition's refreshes, but also because Steam's VR userbase doubled over the course of 2018
Statistics is a bit misleading here mind you, as Doubling of Steam's VR users only brought this figure to 720,000 players, so we're still not talking about mainstream, but it's definitely closer than ever.
Valve will be hoping to tip this figure towards a million with Index, although that will greatly depend on pricing and specs.
You can find Valve's Index page screenshots here.