In certain parts of the Northeast, it is traditional to put brown gravy on French Fries. It has a name but I forgot what it is.
As for the vinegar, it's a malt vinegar especially for Fried fish but people ended up also putting that on French Fries
BTW, everyone always alludes to commercial hamburger from nationally known Hamburger chains as being a little better that horsemeat. Nothing could be further from the truth. The beef that goes into McDonald's, Wendy's, Burger King, et al., would probably cost you twice as much at your local supermarket (if they could even get the recipe). The reason for this is simple; it's known as competition.
One area where they really slipped was McDonald's fish sandwich. The fish in all major chains used to be Cod fish and I think it was Arthur Treacher's who first really promoted malted vinegar to put on the fish (a British tradition). I used to love McDonald's fish sandwiches but when I recently had one I threw half away. You see at one point in the sixties and early 70's McDonald's was the largest buyer of cod fish in the world and McDonald's cold no longer afford it. Yet believe it or not, back then Cod Fish was really looked down upon by the average American so Ray Krock insisted his restaurants bill it as "North Atlantic White Fish." Well we now know how America suddenly fell in love with cod and it got so expensive that you actually now get what is true "North Atlantic White Fish" a change that occurred many years ago and is a fish considered along the lines of carp by much of the American population. Now it's up there in cost with Cod but has viturally no flavor and what flavor it does have I compare with carp! Go figure!