How do you know? Do you know someone?
They can shred their files. But not all the copies of the non-disclosure agreements that have been signed over the years. Unless only the church got to keep a copy. If so....
I have no inside information.
But I’m not stupid (although many would debate that).
If the Vatican is in control of the documents, and the documents incriminate them, why wouldn’t they shred them? Who’s going to stop them?