$ git clone -n https://src.fedoraproject.org/rpms/rubygem-stomp.git /var/lib/mock/f45-build-35340-694/root/chroot_tmpdir/scmroot/rubygem-stomp
Cloning into '/var/lib/mock/f45-build-35340-694/root/chroot_tmpdir/scmroot/rubygem-stomp'...
$ git fetch origin bf0e0467bc9a595f4bc71ff756581aa9d16d13c8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-stomp
 * [new ref]         bf0e0467bc9a595f4bc71ff756581aa9d16d13c8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bf0e046 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild