Manual:$wgDisabledVariants

Language, regional and character encoding settings: $wgDisabledVariants
Disabled variants for language variant conversion.
Introduced in version:1.16.0 (r56560)
Removed in version:Still in use
Allowed values:(array)
Default value:[]

Details

Disabled variants for language variant conversion.

example:

$wgDisabledVariants[] = 'zh-mo';
$wgDisabledVariants[] = 'zh-my';

or:

$wgDisabledVariants = array( 'zh-mo', 'zh-my' );