This is a maintenance category, used for maintenance of the Wikipedia project. It is not part of the encyclopedia and contains non-article pages, or groups articles by status rather than subject. Do not include this category in content categories. This is a tracking category. It builds and maintains a list of pages primarily for the sake of the list itself. They are not part of the encyclopedia's categorization scheme. This category is hidden on its member pages—unless the corresponding user preference (Appearance → Show hidden categories) is set. These categories can be used to track, build and organize lists of pages needing "attention en masse" (for example, pages using deprecated syntax), or that may need to be edited at someone's earliest convenience. These categories also serve to aggregate members of several lists or sub-categories into a larger, more efficient list (discriminated by classifications). Administrators: Please do not delete this category even if it is empty! This category may be empty occasionally or even most of the time.

This category is used to track ((Lang)) and ((Lang-??)) templates where a three-character language subtag (ISO 639-2, -2T, ISO 639-3) has been internally promoted to an ISO 639-1 two-character subtag. Three-character subtags should be replaced with the equivalent two-character subtag. This category is used only by Module:Lang. Articles listed here are sorted by the three-character language subtag.

Where these promotions occur, a hidden message is also available. Editors who wish to see the messages may do so by updating their common or skin CSS stylesheet to include:

.lang-comment {display: inline !important;} /* show lang messages */