Interesting to think that, with a little information, you could pull up the cryptocurrency transaction (assuming it's not a secret ledger like zcash) and trace how the FBI funded the wallet.
Here's one https://storage.courtlistener.com/recap/gov.uscourts.nysd.42... for the sentencing submission for https://en.wikipedia.org/wiki/Paul_Le_Roux which reveals some pretty personal and operational information.
There's one about a Colombian paramilitary leader/drug trafficker turned informant which improperly redacted all the people he informed on: https://storage.courtlistener.com/recap/gov.uscourts.dcd.184.... This is from like a decade ago but goes to show how this kind of thing can literally put people's lives at risk.