Yeah, at a glance—not digging into specifics—the vast majority of them fall under one of four categories:
Things that are not classified by virtue of having never been classified.
Improperly labeled documents that are probably fake.
Declassified documents.
I don't know for sure, but at least some seem likely to be things that are already in the public sphere in one way or another (whistleblower etc). Not accidental releases of classified docs.