I'll save everybody else 120s: if you didn't get penalized for filing your taxes late during covid, move on.
So for example, if you were a contractor who paid your taxes on April 15 (rather than making quarterly payments).
From the IRS?
> Overpayment interest for the 2020–2023 disaster period.
and refers to the interest that the IRS will pay you if they owe you money (a refund) that they don't manage to return to you in a timely manner.
(All of this is explained on the main IRS website: https://www.irs.gov/payments/interest)