Manual:$wgDummyLanguageCodes

Details
This global variable contains an array of language codes that don't have a corresponding set of translated help>Special:MyLanguage/Help:System message|system messages and never will.


 * In most cases they simply map directly to another language code. These codes are left over from renames, or other legacy things.


 * "qqq" is a dummy "language" for documenting messages.


 * "qqx" (since ) is a dummy "language" that can be used with "&uselang=qqx" to view the message names in the interface.

These language codes are excluded on the installer as selectable user or content languages.

Since , they are excluded when running the transstat.php man>Special:MyLanguage/Manual:Maintenance scripts|maintenance script (used for generating stats>Special:MyLanguage/Localisation statistics|localisation statistics).