Common/Util/Money.php
static public function getRoundingIncrement($currency)
    {
        if (isset(static::$increments[$currency])) {
            return static::$increments[$currency];
        }

        return static::$increments[$currency] = static::getCurrencyBundle()->getRoundingIncrement($currency);
    }
static public function getRoundingIncrement($currency)
    {
        if (isset(static::$increments[$currency])) {
            return static::$increments[$currency];
        }

        return static::$increments[$currency] = static::getCurrencyBundle()->getRoundingIncrement($currency);
    }
Returns the currency rounding increment.

@param string $currency

@return float|int|null