Is this behavior intentional?

>>> str = len
>>> x = 'foo'
>>> f'{x!s}'
'3'
>>> '{!s}'.format(x)
'foo'

Or similarly:

>>> import builtins
>>> del builtins.repr
>>> f'{x!r}'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'repr' is not defined