All StackExchange sites have "Unanswered" menu item in their navigation. For example this one:
Except for Stack Overflow and its localized versions. While the menu (AKA left nav) for Stack Overflow is different from every other site (although I don't see obstacles to add "Unanswered" menu item there too)
menu items for localized Stack Overflow look the same as the rest of the network websites except missing "Unanswered" menu item. Screenshots for SO in Russian and SO in Portugese (but the same is true for SOes and SOja):
So can the "Unanswered" menu item be added for all localized Stack Overflow sites and probably Stack Overflow itself?