The basic idea of this is to have a variable that can only be used in the same script it is defined/declared scope. So even if you import the script to another file you still can't access that variable. Basically a local scope but for the script file. Sorry if i'm bad at explaining.
Because normaly you can just do this:
Script a (the script with the variable)
scriptvar = 21
def somefunction():
return "banana"
Script b (the script that should not be able to access the variable)
import script_a
print(script_a.somefunction())
print(script_a.scriptvar)
Script b should return
>> banana
>> AttributeError: module 'script_a' has no attribute 'scriptvar'