Template:Hidecat/doc

undefined is used to automatically hide categories. It also leaves behind a message telling other readers that the category has been hidden.

Usage
On category pages only, type.

Please note that categories generally should not be hidden. This template is only for use in exceptional cases where there is good cause to hide categories. Remember, too, that the hiding of categories can be easily overridden by users who explore their Special:Preferences just a bit.