MediaWiki:Categorytree-member-num is displayed on category pages with sub-categories. It shows counts of sub-categories and pages.
It is set to
($5) by default.
|$1||Number of subcategories|
|$2||Number of articles (not including category pages or file pages)|
|$3||Number of uploaded files|
|$4||Total number of member pages, including category pages and file pages|
|$5||Something close to ($1 C, $2 P, $3 F) but with anything that is 0 omitted.