Inspector general
An independent watchdog inside a federal agency, empowered to audit and investigate it and to report findings to Congress.
An inspector general is an oversight office placed inside an agency but deliberately insulated from it, with authority to audit programmes, investigate misconduct, and publish what it finds. Reports go to the agency head and to Congress at the same time, which is the structural feature that makes them hard to bury.
Their reports are unusually good source material: they are public, they are works of the United States Government and therefore not copyrighted, and they typically state a finding, the agency's written response, and whether the office considers the response adequate. That third element is where the substance usually sits.
Much of the work is following money: whether a programme spent its appropriations on what Congress said, and whether the requirements in the Code of Federal Regulations were actually applied.
What the federal government did, once a day.
One email each weekday: the rules, filings, votes and Fed decisions that actually changed something, each one linked to the document it came from.