The "true" (old) MediaWiki documentation on search is still on Meta, it
needs to be rewritten on
mediawiki.org (PD and up to date):
https://meta.wikimedia.org/wiki/Help:Searching
Nobody reads the help pages, sure. That's why they should be linked from
the special pages etc. as some extensions already do.
<https://bugzilla.wikimedia.org/show_bug.cgi?id=43591>
Nemo