Here’s what we learned from the indictment.

Federal prosecutors unsealed indictments on Friday against former President Donald J. Trump and one of his personal aides, Walt Nauta, revealing devastating new details about a more than yearlong investigation into Mr. Trump’s handling of classified material.

The 49-page indictment, containing 38 counts and seven separate charges, gave the clearest picture yet of the files that Mr. Trump took with him when he left the White House. It said he had illegally kept documents concerning “United States nuclear programs; potential vulnerabilities of the United States and its allies to military attack; and plans for possible retaliation in response to a foreign attack.”