User blog comment:DaNASCAT/Technical Update: February 24, 2016/@comment-1251315-20160226092631/@comment-1251315-20160226092935

This is a bug caused by MediaWiki not implictly allowing undeletions based on just having "undelete". See mw:Help:Undelete: Content Moderators require the additional user right "deletedhistory" to undelete things. This should be fixed as it is currently misleading.