The category "Category" is a special category. (Also, the "Category" category is a special category)
Articles marked "Category" serve as descriptions for a Category. When viewing a category the content of any article of the same name as the category, with a category of "Category" is shown above the list of articles. For example, the text you are reading right now.
When articles with a category of "Category" are edited, they don't show up in the list of "Latest Updates."