Why does TurboTax require Box 'd' Control Number to import W2s if it is not required by the IRS and has no purpose in filing taxes?

Box 'd' Control Number on my W2 is blank/empty. I've come to learn by searching for help on this site that the IRS does not care about this field, nor does TurboTax really need it, as it's just an internal number some payroll departments use.