Search within a category page on a MediaWiki site

I’m trying to search for text on a category page of a MediaWiki website. But the search seems to only work on article pages. How can I also search on category (or all) pages on a MediaWiki website?

This question is similar to this one: Search within a category on a MediaWiki site

Therefore, I want to emphasize, that I am not asking about the search on article pages of a certain category, but about the search on category pages themselves, as the may contain text as well, allongside the listing of subcategories and articles.