Board Thread:News and Announcements/@comment-10473115-20160316184301

Categories listed at the bottom of the page are supposed to help the reader to navigate. Maintenance, cleanup, administration and other categories, which are not part of the content of the article, should be hidden. Hidden category is created by adding magic word " __HIDDENCAT__ " to the category page. It will automatically put that category also to Category:Hidden categories.

This feature hasn't been used much in our database but I'm planning to make a few maintenance categories hidden. Active editors who want to see hidden categories, can make them visible by adjusting Help:Preferences. 