In the Czech example, how is it obvious that `few` stands for 2, 3, 4? Is that just how the concept of "few" (note the English term) is defined and understood by all Cezch speakers and thus this language specific meaning is encoded by Mozilla to map to the range 2-4? My point is that while there might be a concept of "few" that does map uniquely to that range, I am not sure naming the keyword "few" is the right name…
The rules for cardinal numbers in Slavic languages are quite complex. "few" is not just 2, 3, 4, but any number less than 100 ending in 2, 3, 4. You have to use a function to handle the situation. "few" is basically the function name, which is as good as any.
So for example "1002" is "few" in this sense (even though it's bigger than 100) but "14" is not, even though it's less than 100 and ends in 4.