The SC has given the green light to implement PEP 681 in Python 3.11: https://mail.python.org/archives/list/typing-sig@python.org/thread/JWMSWJ6JZJNNG3JKPBYDMQUUHZFD2FZL/

I'll send a PR shortly to add the runtime implementation. As with PEP 655, I'll hold off on documentation to make sure we get the runtime code in before the feature freeze in a few weeks.

cc @debonte @erictraut