How free variable value is determined within nested closure?

Question

I have created a nested closure which looks as below:

def incrementer(n):
    def inner(start):
        current = start
        def inc():
            nonlocal current
            current += n
            return current
        return inc
    return inner

fn = incrementer(2)

Now, when I print value of co_freevars for fn I get below output:

print(fn.__code__.co_freevars) -> ('n',)

My understanding is that it should be ('current', 'n') because there are 2 free variables here.

Why print(fn.__code__.co_freevars) is not printing ('current', 'n')?