Manual:$wgMimeInfoFile

Details
Sets the MIME type info file, which assigns each MIME type to one of several general categories.

The available categories are as follows:

A default  file is distributed with MediaWiki.

Examples:

$wgMimeInfoFile = "/usr/doc/mime.info"; $wgMimeInfoFile = null;  // use a limited set of built-in defaults only (defined in )