Getting detail for 1040 Line 25c

TurboTax Deluxe 2020 shows a number on my 1040 Line 25c (Federal income tax withheld from other forms). TurboTax does not let me zoom in to see the sources of this number. I can't find the source in any of the data I entered into the software. How can I find determine where it came from and how it was calculated?