$ git clone -n https://src.fedoraproject.org/rpms/python-voluptuous.git /var/lib/mock/f40-build-2637301-66211/root/chroot_tmpdir/scmroot/python-voluptuous
Cloning into '/var/lib/mock/f40-build-2637301-66211/root/chroot_tmpdir/scmroot/python-voluptuous'...
$ git fetch origin 8dc57c74bde37b5b13c5122bad93443c4ef895b1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-voluptuous
 * [new ref]         8dc57c74bde37b5b13c5122bad93443c4ef895b1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8dc57c7 New upstream source 0.14.2