Chinese says Sarsaparilla
It tastes like root beer. When I drank A&W I almost couldn’t tell them apart. When I had it in the states I swore it was Heysong sarsaparilla drink.
At one time that particular brand was called “Root Sars”, right after the SARS epidemic too.
It’s pretty good for the price. Tastes like root beer
Don’t know if you care, but we can see your face in the reflection. You may wish to remove the photo.
I remember trying this a couple of years ago but it didn’t taste too good to me - more like sarsaparilla than root beer, and kind of salty IIRC (although I think there’s two different versions). Not at all like A&W root beer in my opinion. I quite like root beer from time to time when I can find it, but I’ve never felt inclined to buy this again.
They have salted root beer. That explains why yours tasted salty. I have no idea why salt is added.
Where do they sell this?
I’ve been told they drink it with salt as a sort of medicine.
Carrefour
I kind of want to try this but don’t want to go all the way to Carrefour, any convenience stores?
I’ve seen some in 7-Eleven and like every other convenient stores. But I’m not sure if they are salted.
If you’re close to Costco, further down xinshu rd is a mini market. It’s open 24 hours a day. They will have most stuff Carrefour has. I find their prices are often on par with Carrefour so I have on occassions shopped there instead of Carrefour. It’s across the street from a Formosa gas station.
Many convenience stores have at least one variety. For salty you’d want to look for the orange one I think, not the red one (original):
I like the red original one better.
I guess almost everyone does ^^
I saw the same stuff as the OP’s picture in PXMart the other day, and also wondered if it was worth a try. (Since root beer is the only soft drink I actually like, bar ginger ale on days when the stomach is a little queasy.)
I like my ginger ale with ginger. No ginger no Ale.
I think I might actually have bought both at the same time to see what the difference was, and found one of them to be unpleasant and the other to be both unpleasant and salty. 
It was 3 or 4 years ago though, so I don’t remember exactly - I just recall the feelings of (i) elation at finding root beer in Taiwan and (ii) disappointment when trying said product. Little was I to know that this would turn out to be but the first of many such experiences with food and beverage purchases in Taiwan.
I think I’ve mostly seen it in Wellcome, where it seems to have been a regular product for several years.