I just noticed some very unexpected behavior. I'm using ProBuilder 5.0.3, and FBX Exporter 4.0.1. If I select a ProBuilder object, and choose "Game Object -> Export to FBX", this will have the side effect of removing the ProBuilder MeshFilter from the object, effectively the same as if you strip PB components from the object. Is this a bug? Is this somehow a necessary behavior? Is this a defect in ProBuilder, or FBX Exporter?