I'm very interested in understanding this as well. Usually with PBR based texturing you have a diffuse, normal, metalness or specular and ao maps. But as you mentioned they are using PM which seems to be several maps combined which makes it very hard to understand and replicate without more knowledge. I also have trouble just saving a new material, and if we could get some info about what type of dds settings they use would also help to create textures.
