Oh, it's actually pretty simple if you've spent more than five minutes reading about food chemistry.
Pepsi isn't made by squeezing a bunch of Pepsi fruits together, despite what some people apparently think.
First, you make a concentrated syrup. That's mostly sugar (or high-fructose corn syrup in the US), water, caramel color for the brown color, phosphoric acid for the tang, caffeine, preservatives, and a proprietary blend of flavorings. The exact flavor formula is a trade secret, but it's basically citrus oils, vanilla, spices, and aromatic compounds. No, there isn't a magical "Pepsi essence."
Then—and this is the part people somehow always miss—you don't bottle the syrup by itself. The bottling plant dilutes it with precisely filtered water at a fixed ratio (roughly 5:1 water to syrup, depending on the formulation). They chill it because cold liquids absorb CO₂ more efficiently, carbonate it under pressure, fill the bottles or cans, seal them immediately, and ship them.
That's it.
It's not handcrafted by monks in the Appalachians. There's no secret underground spring. There's no employee standing there whispering the recipe into each can for "authenticity."
It's industrial food manufacturing. The impressive part isn't the ingredients—it's that a Pepsi bought in Sydney tastes almost identical to one bought in New York because the process is engineered to be absurdly consistent.
But sure, keep telling people it's "just brown sugar water." That only ignores about a century of food science and process engineering.
Hope this helps, OP.