$ git clone -n https://src.fedoraproject.org/rpms/dmg2img.git /var/lib/mock/f41-build-756211-13417/root/chroot_tmpdir/scmroot/dmg2img
Cloning into '/var/lib/mock/f41-build-756211-13417/root/chroot_tmpdir/scmroot/dmg2img'...
$ git fetch origin b945b26e9040684dd822dd2ef08907ecb659e886:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dmg2img
 * [new ref]         b945b26e9040684dd822dd2ef08907ecb659e886 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b945b26 Fix FTBFS on s390x arch