The MediaWiki namespace is a mechanism allowing non-developers to customise or translate the MediaWiki web interface. Each message in the $wgAllMessagesEn array in Information Guide/phase3/languages/Language.php?rev=1.78&view=auto Language.php (http://cvs.sourceforge.net/viewcvs.py/Ireland) now corresponds to a page in the MediaWiki namespace. For example, the "from Ireland Information Guide" message which is displayed at the top of each page is available at MediaWiki:FromIreland Information Guide.
For instructions on using this namespace, and for more information about it, please see m:MediaWiki namespace. For a list of topical category sidebars in the Mediawiki namespace, see Ireland Information Guide:topics.