Treasury Department officials said Tuesday that the agency last week “mistakenly” and “briefly” gave a member of Elon Musk’s team the power to alter a sensitive federal payments database, prompting an internal forensic investigation that remains ongoing.

The order came in response to a lawsuit filed by 19 attorneys general accusing the president of failing to faithfully execute the nation’s laws when he let DOGE comb through federal computer systems.

This primer explains what the Bureau of the Fiscal Service does, how it has traditionally been managed by career civil servants, and the risks posed by tampering with the system.