When using the PowerScript Migrator to migrate a nonvisual object inherited from the PB system class nonvisualobject, I observed that the C# class generated is inherited from object (i.e., not inherited from anything). Which begs the question, has Appeon developed or considered developing a class that nvos could be inherited from? I would think that would have been in the PowerScript.Bridge package but it's not there.
A common ancestor nonvisualobject would implement the events/methods in the attached screen grab.
IMHO, a generated nvo should have an ancestor that implements the interface of NVOs in PB. That would make the code migration effort much smoother. I also noticed that when the code is generated it is missing required using statements, although the C# code that was generated requires them.