Board Thread:New Features/@comment-26402117-20151017123818/@comment-168424-20151018054223

You can use the licensing drop menu for categorization.

Licensing templates can be used in MediaWiki:Licenses that will do the categorization based on which menu item you choose.

You can pass a parameter to a licensing template with something in the above page like this (where you have a Template:Licensing or other standard license templates like Template:GPL):
 * Licenses
 * Licensing|PARAM1|Type of license 1
 * Licensing|PARAM2|Type of license 2
 * Licensing|PARAM3|Type of license 3
 * Free licenses
 * GPL|Gnu public license

You can see how WoWWiki does it on these pages:
 * w:c:wow:MediaWiki:Licenses
 * w:c:wow:Template:Licensing

Community Central has several examples of licensing templates at Category:Image copyright tags.