Wikipedia:Category suppression

Many userboxes and other templates automatically add the pages on which they appear to various categories. This feature is not always desirable, and the process of disabling or suppressing automatic categorization is referred to as category suppression in templates. This guide describes a few different methods of suppressing automatic categorization and provides examples for each method. There are no policies or strict guidelines regarding category suppression; however, this guide describes the de facto methods used to implement category suppression on the English Wikipedia.