Using pre-culled index buffers

There seems to be partial functionality to have alternate static mesh sections with a different set of triangles.

It is set up in UStaticMeshComponent::UpdatePreCulledData() and seems to used throughout the render pipeline. However, that function is never called, and there is no documentation on how to set this up.

Has anyone used this? Does is work? How is it supposed to be used?

Cheers
John