Finding External references in prefab for testing

Unity Engine
1

Hi. I am trying to find which prefabs have external references and just print them out.
I normally go through all the objects in scene. Get the prefabs and then I would like to check if any of the prefabs have external references. Thank you if anyone knows it.
I upload the photo that Unity has this check and I just want to recreate it for automated testing purposes.

4671887--439700--recreate.PNG

2

Ok. Found the solution. Just use

bool canBeSaved = EditorUtility.IsPersistent(gb.instanceObject);