The numbers on the summary menu Deductions&Credits page ?
IT's somewhat dependent on what you entered already...but it can be the total of all withholding on all W-2 for Fed+State+local tax withholding on all your W-2 forms...if you also had a 1099-R form, then it will include all that withholding too....or any other 1099-??? form type that had fed/state/local withholding too..
And if you had a state refund for 2019 state taxes, but you let the state keep part or all of it for 2020 taxes, then that $ amount is added in too.
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I'm not sure it is a particularly useful number to be displayed there.....only if you made a huge entry error...like showing $10,000 or greater than was remotely possible for your total withholding from all sources....then you would go back to all your forms and investigate
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I've never actually found a reason to make any additional entries within that section, but I "guess" it might occur for some unusual circumstance.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*