As far as documents labeled "confidential", or "secret", or "top secret", or "TS/SCI" - that is sensitive compartmented information: I can tell you from my own experience in the White House that most of that stuff, indeed the vast majority of that stuff, is unnecessarily classified because you can get the bulk of it from your local newspaper.
https://www.foxbusiness.com/media/larry-kudlow-trump-search-warrant-charges-utterly-not-believable