PushMaterial cant find any docs?

Is there any documentation on this anywhere? I am trying to add to the material Library but I cant seem to find any docs on this class.

I did everything I could find in the docs for this:
https://doc.babylonjs.com/how_to/how_to_create_a_material_for_materialslibrary

and I ended up with this:

But my mesh does not appear.

This should help: Create a Material for the Materials Library - Babylon.js Documentation

Also the simple material in the library is meant to be used as a template

I did that and copied it over and then modified it, but it seems that the mesh never appears then. But if I toggle points mode or wireframe the shadow updates?

Ill try doing a direct copy of the simple material and try to get that running I guess, then implement one thing at a time till it works.