This is not a real "category" to be added to the page's information, but this page will list all pages that have remarks of missing sources.
An existing [citation needed] does NOT mean that the information is wrong or in doubt, it merely means that the exact source (page number, website etc) is missing and should be added.
How to use
Wherever needed, write %CN% to create [citation needed]. The article will be added to this list automatically.