Data for Estimated taxes entry on 1040-SR, line 26 (2020).

Just received a bill for additional taxes owed from FY 2020.

The discrepancy is from Line 26 on the 1040, "Est tax payments, and amount applied from 2019 return".

Can someone tell me where this value comes from?  What data compiles the entry?

I can only compile a partial amount from looking over the return.

The IRS and I (TbTx) have a  $4,708 difference, and the IRS is only showing a $2,000 payment of the total amount of $6,708.

 

thanks