How about everything. He was assigned the case on 12/7 and issued a sua sponte production order 5 days later. He smells bullshit. That's the only possible explanation for this. The order cites Brady v. Maryland, which is controlling in re the Federal Rules of Evidence, along with Giglio (among others). Short period of time, plus the docket entry stating the feds shall produce "….any evidence in its possession that is favorable to the defendant and material to either the defendant's guilt or punishment."
This final paragraph of his order is also quite telling.
"Finally, if the government has identified any information which is favorable to the defendant but which the government believes not to be material, the government shall submit such information to the Court for in camera review."
He's saying that he doesn't trust the government to determine what's material and what is immaterial, so if they find something that makes Flynn look good, the government must produce it to the court and Sullivan determines its materiality.
Standing order - https:// www.courtlistener.com/recap/gov.uscourts.dcd.191592/gov.uscourts.dcd.191592.10.0_2.pdf