There's this:
"On December 20, as Pompeo later told me, just hours before his
resignation, Mattis gave Pompeo not only his resignation letter but also
other documents, one particularly important here. This was a draft public
statement on the operational plans for the Afghan withdrawal, which
basically preempted whatever Trump might say about it in his January State
of the Union speech. Stunned, Pompeo told Mattis he simply could not
release such a document and that there was no way to edit it to make it
acceptable. Mattis asked if he would at least send it along to me, and
Pompeo said he knew I would agree with him. Neither Pompeo nor I knew
at the time that the Defense Department had drafted an “execute order”
elaborating what the draft statement said, and distributed it to US
commanders and embassies worldwide, all part of Mattis’s resignation
scenario. We obviously understood this only hazily in all the confusion, but
it produced an explosion of press stories. It reflected a common Mattis
tactic, one of spite, to say, in effect, “You want withdrawal? You’ve got
withdrawal.” They didn’t call him “Chaos” for nothing."
Pages 201-202