code: private void parseSupplementalCurrencyData(JsonObject root) {
      JsonObject fractions = resolve(root, "supplemental", "currencyData", "fractions");
      for (String code : objectKeys(fractions)) {
        CurrencyData data = getCurrencyData(code);
        JsonObject node = fractions.get(code).getAsJsonObject();
        data.digits = Integer.valueOf(string(node, "_digits"));
        // Note: _rounding = 0 for all currencies in the modern data set.
      }
    }
docs: Parse supplemental currency data.