Kraft cheese is made with standard real cheese ingredients. They add emulsifiers to it in order to lower the melting point to make it better on a burger or grilled cheese. The percentage of emulsifiers and moisture the slices have is the only reason it can't be legally defined as "cheese". But unlike other things, such as fake ice cream having to be labeled as something like "frozen dairy dessert" because it was made cheaper without enough milkfat and ending up with a worse tasting product, Kraft is just because they wanted their cheese to melt easier.