The indictment accuses President Trump of withholding documents containing “classified markings,” a very specifically deployed obtuse wording intended to create the implication of something nefarious where nothing nefarious exists. It is entirely possible for a person, any person, especially a person who follows the news, to possess documents containing “classified markings.”
There is a big difference between a classified document and a document containing classified markings. As an example, anyone who has looked at the Carter Page FISA application, made public in July 2018, has reviewed a document containing “classified markings.” When a document is declassified, they do not remove the markings.
This language is the underpinning of the entire DOJ/FBI framework that predicated the raid on Mar-a-Lago. Specifically, neither NARA nor the DOJ-NSD requested President Trump or his team to return Classified Documents. The DOJ demanded the return of any documents that contained “classified markings.”