Paradise
I keep wondering how can pardon be an enforcable legal document if it is classified and hidden. Typically a pardon is an official letter and placed in the Federal Register to become legal. If a pardon is classified, then it violates the Executive Order 13526 (thus violates law) and the EO versions before 13526.
On Ford pardoning Nixon, he specied the accusations leading to impeachment so it was not really an all inclusive get out of jail free card.
ThanQ for the additional info and your research on the secret pardons issue.