Currently, the variable names ($wg) are displayed in Special:ManageWiki/settings, but not in Special:ManageWiki/namespaces. I think it would be helpful to see them in Special:ManageWiki/namespaces as well.
This is a change I've been planning to do for awhile. I want to make ManageWikiNamespaces more consistent with ManageWikiSettings. Starting with adding an actual help message to ManageWikiNamespaces, and changing the name fields to be like ManageWikiSettings.