$ git clone -n https://src.fedoraproject.org/rpms/maven.git /var/lib/mock/f40-build-2525805-61811/root/chroot_tmpdir/scmroot/maven
Cloning into '/var/lib/mock/f40-build-2525805-61811/root/chroot_tmpdir/scmroot/maven'...
$ git fetch origin 67f34b5e38a928cfba575620204d0c41245b5d35:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/maven
 * [new ref]         67f34b5e38a928cfba575620204d0c41245b5d35 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 67f34b5 Rebuild