We started to get questions about advanced search that are not related to the extension and seem to come from 3rd party wikis. See this for example:
https://www.mediawiki.org/wiki/Topic:V05p9cddxhbflzqq
I suspect that some 3rd party sites installed Advance Search and we have somewhere a link to our discussion page hardcoded that people misunderstand as the help page about the search of the corresponding wiki.