$ git clone -n https://github.com/xcp-ng-rpms/mdadm.git /var/lib/mock/v8.3-incoming-8998-27901/root/chroot_tmpdir/scmroot/mdadm
Cloning into '/var/lib/mock/v8.3-incoming-8998-27901/root/chroot_tmpdir/scmroot/mdadm'...
$ git fetch origin 087d6612feeadca9557c536597fa268359ff26aa:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/mdadm
 * [new ref]         087d6612feeadca9557c536597fa268359ff26aa -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 087d661 Merge branch 'XS-8.3' into 8.3-XS-1666