Currently, if you try to subscript a non-generic type you will get an error:

>>> int[str]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'type' object is not subscriptable

Yes, 'type' objects are usually not subscriptable, but list[str] works, and it is not clear from the error message for what type it is failed.

The following PR changes an error message:

>>> int[str]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: type 'int' is not subscriptable

New changeset ab9301a28fa431d7a32163126fc96de3b2ce6107 by Serhiy Storchaka in branch 'main':
bpo-46927: Include the type's name in the error message for subscripting non-generic types (GH-31694)
https://github.com/python/cpython/commit/ab9301a28fa431d7a32163126fc96de3b2ce6107