How Trump, other high earners had their taxes leakedIRS consultant Charles Littlejohn, who faces up to five years in prison, didn't use a particularly elaborate scheme to obtain thousands of confidential returns from wealthy people.
Source: How Trump, other high earners had their taxes leaked (https://www.politico.com/news/2023/10/16/trump-littlejohn-tax-returns-irs-00121791)