Can't save the variable of the prefab

Unity Engine
1

I have already created a prefab that have serveral public variables(gameObject, int, so on…)

And I modified this prefab from the scene and clicked the ‘Apply’ button on the Inspector panel
to save the original prefab in the Projector panel.

But the changes didn’t applied to the original prefab, with the variable name of the prefab turned the bold style letter

The variable(game object) of the prefab can’t use the game object in the scene(which is at the hierachy panel) ???

2

it can if you will find this GO by tag/name, or if you’ll make a prefab for it too.

3

“…find this GO by tag/name” means that I have to use the “GameObject.Find(“name”)”…
I think, it’s better than use the dragging and link from Hierachy to Project than using Find() because Find() have to check through all the game objects in the scene to find one game object.

Doesn’t the prefab use the game object variable by dragging and link from Inspector to the Prefab ???