@peterdrake I think that’s a non-prefab that has prefab like behavior. You can’t unpack it. Usually it’s a transform hierarchy imported as part of a mesh. It has prefab like behavior in that the object will update if the source asset changes. Not sure if it has a name.
@andykorth It feels like if something has a special symbol it should also have a name.
@peterdrake I agree, but I think Unity doesn't want to take away the ~mystery~ of the engine by documenting it. The internal icon names though are: