This template is meant to be used for content category pages. It produces a box indicating that all articles in the current category should be listed in the category's page, regardless of whether or not they are listed in one or more subcategories. See Wikipedia:Categorization#Subcategorization for more details. See {{Geography parent category}} for a similar template that lists PetScan queries for use in maintenance.
For convenience, all American film actors should be included in this category. This includes all American film actors that can also be found in the subcategories.