Manual:$wgUseGzip

Details
When using the file cache, we can store the cached HTML gzipped to save disk space. Pages will then also be served compressed to clients that support it. In older versions of MediaWiki it also controlled if normal (non file-cached) pages were gzipped.

THIS IS NOT COMPATIBLE with ob_gzhandler which some users may have enabled in LocalSettings.php (see )! If you enable this, remove that setting first. It is also incompatible with automated gzipping done on the server side (e.g. mod_deflate) and zlib.output_compression

Requires zlib support to be enabled in PHP.

Between 1.2.0 and 1.3.0 (inclusive) the default value was true if the function 'gzencode' is defined, otherwise false. For prior and later versions it defaults to false.