What's on the menu? Duh!
Anti-branding as a concept isn't new to the Japanese. The successful Muji stores there are based on the idea of "no brand" and in fact Wikipedia says the store's name is "derived from the first part of Mujirushi Ryōhin, translated as "No Brand Quality Goods."
This looks like a pretty cool location and a neat no-branding of a familiar product. It would be even cooler applied to a real hamburger joint serving real quarter-pound hamburgers.