This category is a "template category". It is used to categorise pages which are in the template namespace. The category is part of the Wikipedia project infrastructure and should not be used to categorise pages belonging to other namespaces, in particular articles.
How to add a template to this category
To add a template to this category, use the following code at the end of the template:
If you add this code at the end of the template, please make sure that the opening <noinclude> starts on the same line as the last char of the template code. Experiments revealed that some templates became seriously defunct when that rule was violated.