Translations:Help:Namespaces/26/en

The “$1” namespace contains, dynamic lists of other pages. To facilitate this, linking directly to a category page does not output an inline link, but instead includes the page into the associated category page. So the code  causes a category link to appear at the bottom of the page (at the bottom in the box marked “$int-pagecategories”). Clicking on that link takes you to the category page, where this page is visible in the category list.