Big Macs remain on sale at some of McDonald Corp’s franchise locations in Russia despite most of its restaurants reopening on Sunday under new branding and ownership. McDonald’s sold most of its 850 restaurants in Russia to one of its local licensees in May. Some of those reopened Sunday under the new name Vkusno & tochka, or “Tasty and that’s it,” offering a new menu without the flagship burger. But other franchisees have kept their locations open, selling authentic McDonald’s meals in restaurants adorned with barely concealed McDonald’s branding. Their lingering presence highlights the chall…