Open SubDiv, where art thou?

Back at GDC 2017, it was stated that the engine now supports Open SubDiv.

It is buried in the source, but there are zero docs on how its being used.
How are we supposed to know where its located and so on?
How are we supposed to extend its functionality?

I would like to apply it to imported meshes. It is possible on a variety of 3rd party applications, and transferable via FBX. What is UE4’s take on this?

Cheers,

Sterling