$ git clone -n https://src.fedoraproject.org/rpms/maven.git /var/lib/mock/f41-build-1030881-18484/root/chroot_tmpdir/scmroot/maven
Cloning into '/var/lib/mock/f41-build-1030881-18484/root/chroot_tmpdir/scmroot/maven'...
$ git fetch origin d9cff31cffef3d243d3b75c842428d6f78b897e9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/maven
 * [new ref]         d9cff31cffef3d243d3b75c842428d6f78b897e9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d9cff31 Rebuild