Special counsel Robert Mueller’s office asked a court for an 11-day extension on a filing deadline Tuesday — claiming that, for the time being, key attorneys on their team were too busy with “the press of other work.”

The reference immediately raised eyebrows among close watchers of the special counsel’s work — because there are no known important deadlines in Mueller cases coming up. So what, then, is Mueller’s team so busy with at the moment?

For months now, rumors have been rampant that Mueller’s final report and the conclusion of his work are imminent. Some top attorneys on his team are leaving, and his top FBI agent has already left. All the specific predictions about when, exactly, the report would be done have turned out to be wrong so far, but all things must come to an end eventually.

Now, Tuesday’s request comes in response to a request by the Washington Post to unseal certain materials related to former Trump campaign chair Paul Manafort. The deadline for Mueller’s team to respond was supposed to be this Thursday, March 21 — but they’ve asked it be extended to April 1. Here’s the key paragraph:

“The counsel responsible for preparing the response face the press of other work and require additional time to consult within the government,” Mueller’s team writes.

The lawyers referenced are Michael Dreeben and Adam Jed. But it’s unclear what they’re busy with at the moment. There are no imminent deadlines in Roger Stone’s case, or the two appeals from a Stone associate and a mystery company. There’s a March 25 deadline in the Russian troll farm case, but Dreeben and Jed don’t appear to be involved in that filing.

They seem to be working on something else, and that could well be Mueller’s report. Both Dreeben and Jed are appellate attorneys rather than trial prosecutors. So it would make sense if they were spending their time on Mueller’s biggest task of all, his report, for which there are unsettled legal and constitutional issues about what information can be made public and how to handle Trump’s role as president. It is also possible, though, that the pair are working on some other secret matter we don’t know about.

In any case, Mueller’s team expects they’ll have more free time to file a response in this Manafort matter by April 1. It’s hardly definitive, but it’s an interesting tea leaf as we await the special counsel’s findings.

For more on the Mueller probe, follow Andrew Prokop on Twitter and check out Vox’s guide to the Trump-Russia investigation.