On Friday, Trump campaign chairman Paul Manafort became the latest member of Trump’s team to plead guilty to felonies in federal court. Manafort pleaded guilty to one count of conspiracy against the United States centered around bringing into the country $60 million in unreported cash, and one count of Conspiracy to Obstruct Justice through witness tampering. Surprising almost everyone, Manafort’s deal was not a simple plea of guilty to avoid the cost and burden of a second trial, but was accompanied by a 17-page cooperation agreement in which Manafort agrees to cooperate extensively. Extensively.

Your client shall cooperate fully, truthfully, completely, and with the Government

and other law enforcement authorities identied by the Government in any and all matters as to which the Government deems the cooperation relevant.

Included is an agreement to be questioned on the record about any subject, to provide any document in his possession, and to testify truthfully, fully, and completely before any jury where he is requested. It’s a genuine everything-to-the-walls agreement to cooperate on every point at any time. It’s also something that clearly took some time to negotiate and draft, making it all the more amazing that the agreement was a stone cold secret right up until Manafort stepped into court on Friday. Robert Mueller apparently keeps his team in a submarine, because they do not leak.

What does Manafort know? Well, he was there in the Trump Tower meeting. He was there when Papadopoulos offered up a meeting with Putin and exchanged messages over the potential for getting the stolen DNC emails. Manafort was in near continuous contact with his Russian handlers during the campaign, was directly involved in modifications to the Republican platform that softened language related to Russia, and offered up a personal briefing on the Trump campaign to his favorite oligarch, Oleg Deripaska.

That’s just Manafort. That’s just the parts we know. Multiply that by Gates, who was there longer and involved in the transition team. By Flynn, who was not only partying with Putin but nursing his connections to other autocrats. By Cohen, who didn’t just set up a company to handle Trump’s adultery fees, but directly sold his influence for dollars. And by Weisselberg, who wrote the checks to cover everything Trump was up to since forever.

When it’s all put together, Robert Mueller is going to have a fantastically detailed picture of Donald Trump and everyone involved in Donald Trump’s campaign. He’s going to know Trump’s business, his phony charity, his campaign, his transition, and his family.

Paul Manafort’s first trial, the second set of charges, and the cooperating agreement are all a snapshot of not just Manafort, but Mueller. They’re a picture of how he’s operating this investigation: Diligently, step-by-step, piling one piece of evidence on another, confirming each item again and again, providing detailed transactions and just plain overwhelming information. The agreement shows that what we know of the Muller investigation remains not even the visible part of a vast, inexorable iceberg grinding steadily ahead.

In making his deal with Mueller, Paul Manafort put in a special request. According to CNBC, Manafort “told prosecutors he preferred that they seize his apartment in Trump Tower than give up one of the four bank accounts.” Giving up his Trump Tower apartment was likely a good move for Manafort. After all, even should he emerge from prison in just a few years, it’s not somewhere he’s likely to feel comfortable living.

And Trump Tower … could always show up on a list of assets under forfeiture should it turn out that one of the things Robert Mueller knows, is just how much Trump has used money-laundering of illegal foreign funds to finance his US deals.