Manual:$wgCapitalLinkOverrides/en

Details
Per namespace configuration for.

Example:

Warning

 * Some namespaces&mdash;Special, User and MediaWiki, and their associated talk namespaces&mdash;must be capitalized.  will not affect them.
 * Since Talk namespaces need to directly mirror their associated subject namespaces, the values for those are ignored in favor of the subject namespace's setting.