Say you are talking to your frat brah. Private conversation. Conversation is wiretapped. Invading that privacy then releasing the identities of those on the call would be unmasking.
They most likely know who we are, but Flynn was different. They unmasked him to set him up.
This is why Sessions recused, and the plan HAD to unfold and let EVERYONE recommit to new crimes. Pardons have timestamps, and only can look backwards. And are ONLY Federal.
Flynn, Rudy and Sessions designed the prosecution side of this, no question. Do note Sessions Alabama AG nickname.
"The Silent Assassin"