[sleavey]

Possibly there needs to be something classified as a sweetener, yes, but the definition of "sugar-free" is apparently also anything with 0.1g or less sugar per 100g, so may it be that there is still a bit of sugar in the sugar-free brands you mentioned?

I'm no expert on this.

[Ndymium]

Looks like in the EU "sugar free" is limited at 0.5g sugar per 100g or ml of product: https://ec.europa.eu/food/safety/labelling-and-nutrition/nut...

I checked one and it contains 0.1g of sugar per 100g, but it's not added sugar, it's contained in the other ingredients. I don't know if it's possible to make it with absolutely 0g of sugar. But there is no separate ingredient "sugar" there.