Manual:$wgContentNamespaces

From MediaWiki.org

Namespaces: $wgContentNamespaces
Namespaces which are considered to contain real content, or articles
Introduced in version:	1.7.0 (r14738)
Removed in version:	still in use
Allowed Values:	Array of namespace indexes
Default Value:	array( NS_MAIN )

Other settings: Alphabetical | By Function

[edit] Details

$wgContentNamespaces exists to allow custom namespaces to be acknowledged as containing useful content for the purpose of Special:Random, Special:Statistics, and {{NUMBEROFARTICLES}}. Useful if additional namespaces also contain "content" which should be considered when choosing a random page or generating a count of the number of articles in the wiki.

The main namespace is considered a content namespace, as are other namespaces in this array, referenced by index.

Example:

$wgContentNamespaces = array (0, 12, 112);