The former president told the group he had a “plan of attack” from a senior military official. Trump characterized the document as “highly confidential” and “secret information” and noted that "as president I could have declassified it.

Sounds like it’s the document that was thought to be a plan Mark Milley (Chairman of the Joint Chiefs under both Trump and Biden) made for invading Iran. There were so many news stories about this, Trump was caught on tape admitting to a crime, but for some reason he wasn’t being charged for this document specifically. Now it looks like he is.