Valve deserves to be beaten with an internet flamebat for naming a SteamVR-specific compatibility layer "OpenVR".
If I'm incorrect and there are merits to it, please enlighten me, but everything I've read about OpenVR (and seen in their git repo) seems to only be an accurate name for where the meaning "Open" == null.
If API + binary blobs + single company control + BSD license is the new definition of open, then... hmm.
They should have called it ValveX. It's the best bad option among worse options (and that's probably why Valve won't put more effort into opening it up until the market matures), but it's not an open standard.
It's not unlike OpenGL though, which does not have a open source reference implementation either. Only the API specifications are open.
Most implementations are closed source binary blobs. Of course there is Mesa, but that is is also a 3rd party implementation. No one would prevent you from building an open source OpenVR implementation.
The purpose of OpenVR is to create a common API for HMD drivers, so that other platforms can implement their own proprietary equivalents of SteamVR or what have you, and everyone's HMD drivers will be interoperable.
I probably doesn't understands everything and you probably have more knowledge than me on that but as far as I understands that's more a standard that a library. You still need to write the actual drivers for your headset and as far as I know, the one for the Vive isn't opensource. OpenVR is still open, it's just the Vive drivers that are not.
If I'm incorrect and there are merits to it, please enlighten me, but everything I've read about OpenVR (and seen in their git repo) seems to only be an accurate name for where the meaning "Open" == null.