My global var is a constant for some reason

Godot Version

Godot 4.3

Question

``extends Label

var scriptscore = 0

func _process(delta):

#print score
self.text = str(GlobalScore)
set_process(false)
await get_tree().create_timer(1).timeout
#add score
GlobalScore += 1
scriptscore = GlobalScore
set_process(true)
``

what exactly is “GlobalScore”?

What is the exact problem? Also how GlobalScore is a global variable? Because i don’t remember any way to create global variables from gdscript.