Coca-Cola uses phosphoric acid. Here's a Coca-Cola bottling plant receiving a delivery of phosphoric acid.[1] It's marked with a 1805 (Phosphoric Acid, Corrosive, Class 8) placard. Of course, it's diluted as the product is mixed. This video shows the ingredients - tap water run through an de-ionizing plant, high fructose corn syrup in tank cars, phosphoric acid by the pallet load, flavoring (the "secret ingredient", in bags), and CO2 as a gas.

[1] https://youtu.be/7V6JO0Rfgas?t=189

The acid seems to interact with torn aluminum (from the mouth of the can) to create a specific taste effect that is addictive, or preferred. My skin also would break out reliably, per can consumed (and still does when I test it out).

I switched from consuming soda from cans (and bottles) 2 decades ago. Drinking from soda fountains exclusively is more expensive at times and certainly doesn't taste as good (being a brown sugar suspension with few additives), but my skin stopped breaking out, my diabetes tests are negative, and my weight is consistent. I'm convinced it's not the soda flavor nor only the sugar nor the carbonation, but the containers and solution related to the acid. Bottled soda has all kinds of nasty effects based on how it's stored and for how long, that soured me pretty early on.

Carbonic Acid, or more specifically drinks with carbonic acid (with or without anything else) have recently been shown to increase calorie consumption.

Phosphoric acid (popular in Coke) is the much more dangerous one eating bone, organs, affecting the liver.

chronically lowered stomach pH is associated with gastrointestinal bleeding