Currently Argument Clinic with a var-positional parameter is only used in few functions (print(), the TypeVar constructor (see #118814) and several set methods), so this is not well tested.

There are several bugs here:

• Keyword-only parameters after the var-positional parameter are marked as positional-or-keyword parameters.
• The number of required arguments for keyword-only parameters was calculated incorrectly.
• Some invalid combination of the var-positional parameter with /, * and deprecation markers are not forbidden or produce unrelated errors.

Linked PRs

• gh-122688: Fix support of var-positional parameter in Argument Clinic #122689
• [3.13] gh-122688: Fix support of var-positional parameter in Argument Clinic (GH-122689) #122852
• gh-122688: Add more tests for var-positional parameters in Argument Clinic #122900