How to display dormant articles in a summary buffer?

Today I wanted to find this one, which I knew was residing as a dormant
article (and thread) in the summary buffer of nntp+news.gmane.io:gmane.emacs.help:
 https://lists.gnu.org/archive/html/help-gnu-emacs/2021-06/msg00854.html

And the only way I found how to do it was to open the nntp+news.gmane.io:gmane.emacs.help
group with 'C-u 15000 RET', and that is... a bit cumbersome.

A google search found
 https://www.math.utah.edu/docs/info/gnus_5.html#SEC66
and gnus-summary-show-all-dormant, which sounded very much like what I
wanted.

But that command wasn't in my gnus and not in the .el files of that gnus
either (emacs 28 gnus).

So the commands have been removed? Why? Was nobody using them?
(the reason I'm asking is that I would have liked to use them now and
would in the future have used them instead of the C-u <number> trick. I
have lots of gmane groups with old dormant threads)

Thanks!

- Steinar