Get monobehaviour variable from prefab

I have some prefabs (not referenced in any script) in Assets folder. How can I get monobehaviour variable from them in editor script?

 

If you just want data holders, use a scriptable object instead of a prefab/gameobject. Other than that, you can reference the prefabs and just get the component as you normally would or you could load them from resources and get the data that way.

Why do you need data from an object which isn't being used in the scene?

 

I'm writing custom inspector and I need some data from prefabs.