Copy-to-clipboard

https://docs.gitlab.com/ee/user/markdown.html#transition-from-redcarpet-to-commonmark
This page has a few code-areas that have a copy-to-clipboard icon in the top right corner of the code box. When you click them… it copies what’s in the code-area to your clipboard.
I haven’t located documentation on how to replicate this???
I see that the page is originally markdown: https://gitlab.com/gitlab-org/gitlab/blob/master/doc/user/markdown.md
And is pulled into a theme? to be displayed as html. Could someone could point me to the section of the theme that handles this?
Been here: https://clipboardjs.com/
and here: https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/1494
and a guthub example here: https://github.com/zenorocha/clipboard.js/issues/94
which works, but doesn’t look as good.
I’ve looked at the source html. It includes the script clipboard.js but doesn’t appear to use it as documented on their site.
Could someone point me to the documentation on gitlab usage, or to an example?
Or better yet, tell me this idea didn’t die on the vine, https://gitlab.com/gitlab-org/gitlab/-/issues/21172 and the function is now available in markdown?
Thanks