Leas-free solder is now the standard due to RoHS, at least in Europe. It doesn't stick as well as Pb-Sn solder though, annoyingly.

I suppose you could try to blend in the 0mm drop shoe slowly, starting from shorter runs, and see how it feels. In any case, the drop measurement is a static measurement and in action the drop "feel" depends on how compliant the midsole is (softer foam means more deviation from "on paper" drop specification)

Well, it might be representative of where the English term is used, I wouldn't draw any more conclusions from that.

I would expect so, why would the English term be used in other languages? At least in Finnish, the term would be "kevytvaellus" (meaning "light[weight] hiking") and in Swedish the term "ultralätt" (lätt=light) is used at least as much as the English term.

Leas-free solder is now the standard due to RoHS, at least in Europe. It doesn't stick as well as Pb-Sn solder though, annoyingly.