$ git clone -n https://src.fedoraproject.org/rpms/copr-keygen.git /var/lib/mock/f45-build-6902-353/root/chroot_tmpdir/scmroot/copr-keygen
Cloning into '/var/lib/mock/f45-build-6902-353/root/chroot_tmpdir/scmroot/copr-keygen'...
$ git fetch origin 151e5431ed2999c5a0c00f07ba61dbf8304251c4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/copr-keygen
 * [new ref]         151e5431ed2999c5a0c00f07ba61dbf8304251c4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 151e543 Update copr-keygen to 2.3-1