This.

Any 501 c 3 charity has to file annual tax documents. While they usually don't owe any taxes they still have to show what their total income, expenses, and charitable distributions were on the tax filings.

Because they are charitable organizations with tax exempt status those tax filings are public record.

And charity watchdog groups go pull those tax filings every year on charities and summarize what's in them.

It's a great service that should be utilized for any contribution. If everyone did that, then scam charities would dry up as they wouldn't get any money.