I found a website the other day which gave you the deficit month by month and you could make excel tables out of the data The pros call that a time series. So, you could google for federal debt download time series and see if you get lucky.
When formulating search terms, it's always best to learn and use the terminology the insiders in a field use.
You could also try
federal debt time series csv, on the theory that downloadable tabular data is most likely to be made available in csv format. You could also try xls, xlsx, xml, etc.