Letter from IRS Interest Income for 2024, says 1099-INT, has a $, but not in normal format. Is this "Interest income" (box 1) or "Interest on Treas.obligations" (box3)?

[rebecca_mcc]

Received check last yr from IRS that was back-stimulus payment I never got previously. Then got this "Statement Showing Interest Income from the Internal Revenue Service," and there is an amount listed, and says 2024, and along the side says "Form 1099-INT." But this is not in the standard layout, and there are no numbered boxes. Do I treat this like my savings account interest statement and call it "Box 1 - Interest Income", or like "Box 3 - Interest on US Savings Bonds and Treas. obligations"? In the print under the brief statment letter, is says "...report this interest as income on your return." So, unclear if that equals box 1, or if since this is a Treasury-related matter, it would go in Box 3?

[Mike9241]

Box 1. this is not US interest on US debt obligations. It's taxed just like interest paid on a late federal refund.