Comment by hilbert42

Could be wrong but I heard phosphoric acid is in similar amounts in all of them for the unusual reason that this inorganic acid actually enhances (brings out) the cola flavor. Seems this doesn't happen with normal carboxylic food acids, malic, citric, tartaric, etc.

It's an odd combination, I think colas are the only instance where a mineral acid is used synergistically with another ingredient to enhance flavor.

Someone with greater knowledge may wish to expand on this.