....and he shall have Power to grant Reprieves and Pardons for Offences against the United States, except in Cases of Impeachment.
Since pardons are conjoined with reprieves and the sentence that is being reprieved must be specified, I say that so must the pardoned be specified, too.
This notion of Biden's that they are not guilty of anything but he's pardoning them anyway is an abuse of the power of the pardon.
-PJ