The following 11 special pages appear to be missing help links, and are listed with a suggested target. This is not an exhaustive list. I'll leave this for a few days for any feedback about the targets before uploading a patch.
- Special:DeletedContributions -> Help:User_contributions (on mediawiki) (same as Special:Contributions)
- Special:Tags -> Manual:Tags (on mediawiki) (Help:Tags is still an incomplete draft
- Special:ComparePages -> Help:Diff (on mediawiki) (same as Special:Diff)
- Special:Undelete -> Help:Deletion_and_undeletion (on mediawiki)
- Special:ProtectedPages, Special:ProtectedTitles -> Help:Protected_pages (on mediawiki)
- Special:UncategorizedCategories, Special:UncategorizedFiles, Special:UncategorizedPages, Special:UncategorizedTemplates -> Help:Categories (on mediawiki)
- Special:ListGroupRights -> Help:User_rights_and_groups (on mediawiki) (Same as Special:UserRights)