MediaWiki:Apihelp-options-extended-description
From I.T. Sparkles
Only options which are registered in core or in one of installed extensions, or options with keys prefixed with userjs- (intended to be used by user scripts), can be set.
Only options which are registered in core or in one of installed extensions, or options with keys prefixed with userjs- (intended to be used by user scripts), can be set.
