MediaWiki User Guide/Extensions

Extensions, as the name implies, are extra pieces of code that extend the features of MediaWiki. While MediaWiki is quite customizable and feature rich without any extensions, extensions often provide features not possible to provide by MediaWiki alone, such as advanced page security, the ability to read and display additional file formats, or even provide ways for other web applications to directly interact with MediaWiki itself. Ordinary users do not have control over which extensions are installed, though some extensions have features that can be enabled and disabled via the user preferences menu (provided the user has an account on the wiki).