Mystery 1099-INT

I've already filed my taxes, both state and federal using TT online just as I have for the past several years. Both my federal and my state returns have both been accepted according to the TT e-mails I have received.

 

Today I received a 1099-INT from the IRS(for 2021)showing "Total Interest Paid or credited" of $15.35 with my correct SSN and a "Payers Federal Identification Number" of 38-1798424. The first box of the form says "Statement Showing Interest from the Internal Revenue Service"

 

I do not own any interest bearing accounts other than my 401k through my employer.

 

I have always filed my taxes early and did not receive an interest refund from the IRS for the 2021 tax year. How do I research this to find out what they are supposedly paying me interest on?