As we know, "Order 66" led the clones to try to kill all the Jedi. But what was the wording of the order itself? Was it simply "kill all Jedi", or was it more complicated?
According to Star Wars: Republic Commando: True Colors by Karen Traviss
Order 66: In the event of Jedi officers acting against the interests of the Republic, and after receiving specific orders verified as coming directly from the Supreme Commander (Chancellor), GAR commanders will remove those officers by lethal force, and command of the GAR will revert to the Supreme Commander (Chancellor) until a new command structure is established.
Note that while this novel isn't considered a (Disney) canon source of information, Traviss is the author of several canon novels set within the Star Wars: Clone Wars continuity including the official novelisation which at the very least makes her word pretty authoritative.