$ git clone -n https://github.com/xcp-ng-rpms/mdadm /var/lib/mock/v8.3-incoming-10729-29267/root/chroot_tmpdir/scmroot/mdadm
Cloning into '/var/lib/mock/v8.3-incoming-10729-29267/root/chroot_tmpdir/scmroot/mdadm'...
$ git fetch origin da9e97e489c0e70b5f8e86b022c4a4676f685d22:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/mdadm
 * [new ref]         da9e97e489c0e70b5f8e86b022c4a4676f685d22 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at da9e97e Merge pull request #1 from xcp-ng-rpms/8.3-XS-1666