Hi,

The following example program returns `sh-case' on Emacs 27 and
olders, however to make it work on Emacs 28 and 29 the third
line has to be uncommented.  So does `describe-key' case.

(with-temp-buffer
  (sh-mode)
  ;;(set-window-buffer nil (current-buffer))
  (describe-key-briefly "\C-c\C-c"))

I don't know when/why those commands were changed to require the
buffer (where the keymap is) to be visited in the selected window,
but now `gnus-article-describe-key\(-briefly\)?' doesn't work
because of this.  A patch to gnus-art.el is attached, though the
one that should be fixed might be help.el.

Thanks.