Red.

It has taken many years, but the mystery of Red flavoring has finally been solved: it's "strawberry-cherry," according to the folks at Walgreens, who have probably violated some kind of top secret trade agreement by putting it right on the label of their Red Soda.

One sip confirms it: this is indeed the same Red as found in popsicles, lollypops, hard candy, and cheap confections the world over.