> It starts with the following list: grep-regexp-alist, gmm-regexp-concat, project-find-regexp,
> shell-dumb-shell-regexp, rmail-secondary-file-regexp, rmail-user-mail-address-regexp,
> tramp-file-name-regexp, whitespace-indentation-regexp, project-or-external-find-regexp... All of which are
> irrelevant to what we search.

Which is why I said elsewhere that without making the candidate
scoring smarter, adding aliases based on namespaces will be much less
useful, perhaps even detrimental.

> What it should list is https://www.gnu.org/software/emacs/manual/html_node/elisp/Regexp-Search.html, but
> also merged with the Match Data documentation, presented in a much more condensed manner, etc.

The above are _commands_ not functions.  The equivalent would be
"C-h a regexp search RET", which does do what you want, I think.