$ git clone -n https://src.fedoraproject.org/rpms/rubygem-yard.git /var/lib/mock/f45-build-35452-695/root/chroot_tmpdir/scmroot/rubygem-yard
Cloning into '/var/lib/mock/f45-build-35452-695/root/chroot_tmpdir/scmroot/rubygem-yard'...
$ git fetch origin a02a8f5e4aeb65ca9677c205fe8f2aaa0262fbd6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-yard
 * [new ref]         a02a8f5e4aeb65ca9677c205fe8f2aaa0262fbd6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a02a8f5 0.9.45