For example, the grouping field for the en_US locale, would contain a 2 item array with the values 3 and 3.
The grouping fields contain arrays that define the way numbers should be grouped. For example, the grouping field for the en_US locale, would contain a 2 item array with the values 3 and 3. The higher the index in the array, the farther left the grouping is. If an array element is equal to CHAR_MAX, no further grouping is done. If an array element is equal to 0, the previous element should be used.