EU has absurd serving size measurements too, but also 100g measurements

In Canada we also have nutrition facts per serving bullshit

It's rounded to the nearest multiple of 10; it could be up to 5 (exclusively), and could still be listed as 0. It's why so many lower-calorie products are listed with a zero-calorie serving size in the US. I'm not sure about the specifics of regulations — if any exist — on selecting serving sizes; this particular example feels a little fishy to me.

I think you can round down and be off by a certain percentage.

Because they are allowed to do their own testing to determine caloric quantity and there is often some flubbing in the recipe during the testing. Kinda like how VWs used to have a different engine mode for emissions tests than normal driving.

Because it is 0g fat

Edit: /s

They don't claim to be sugar-free, at least not the ones made of sugar. Instead, they claim to have 0g of sugar per serving. That is a critical difference.

In that case, they are using synthetic sweetener instead of sugar.