$ git clone -n https://src.fedoraproject.org/rpms/mailprocessing.git /var/lib/mock/f39-build-2240571-53641/root/chroot_tmpdir/scmroot/mailprocessing
Cloning into '/var/lib/mock/f39-build-2240571-53641/root/chroot_tmpdir/scmroot/mailprocessing'...
$ git fetch origin 0e13b851967b56cb0374ab2a28a3f99055b1de7b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mailprocessing
 * [new ref]         0e13b851967b56cb0374ab2a28a3f99055b1de7b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0e13b85 Add Packit config