A "rich range" of anything is contrary to the spirit of JSON. JSON became popular in part because it was a much simpler contrast to technologies like XML that

A "rich range" of anything is contrary to the spirit of JSON. JSON became popular in part because it was a much simpler contrast to technologies like XML that provided a "rich range" of everything. Leaving it unspecified means that JSON as a format is capable of arbitrary precision, without requiring that implementations carry around bignum libraries if their particular application doesn't need them.