$ git clone -n https://src.fedoraproject.org/rpms/rubygem-power_assert.git /var/lib/mock/f45-build-35158-693/root/chroot_tmpdir/scmroot/rubygem-power_assert
Cloning into '/var/lib/mock/f45-build-35158-693/root/chroot_tmpdir/scmroot/rubygem-power_assert'...
$ git fetch origin 71c06bccd07cb18fcaa74d0944f0203b81a20c67:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-power_assert
 * [new ref]         71c06bccd07cb18fcaa74d0944f0203b81a20c67 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 71c06bc 3.1.0