Misc/NEWS.d/next/Library/2021-05-12-16-43-21.bpo-38908.nM2_rO.rst

Fix issue where :mod:`typing` protocols without the  ``@runtime_checkable``
decorator did not raise a ``TypeError`` when used with ``issubclass`` and
``isinstance``.  Now, subclassses of ``typing.Protocol`` will raise a
``TypeError`` when used with with those checks.
Patch provided by Yurii Karabas.