title: MediaWiki, how to add filters to the SpecialPages:Categories page?
body: <p>To better understand the code of MediaWiki, I'm trying to modify directly the source code without creating an extension.</p>
  <p>In the page <code>Special:Categories</code> I'd like to show only the categories which are not created by a <code>Template</code>. How can I modify the query?</p>
  <p><a href="https://doc.wikimedia.org/mediawiki-core/1.28.0/php/classSpecialCategories.html" rel="nofollow noreferrer">https://doc.wikimedia.org/mediawiki-core/1.28.0/php/classSpecialCategories.html</a>
  <a href="https://doc.wikimedia.org/mediawiki-core/1.28.0/php/classCategoryPager.html" rel="nofollow noreferrer">https://doc.wikimedia.org/mediawiki-core/1.28.0/php/classCategoryPager.html</a></p>