$ git clone -n https://src.fedoraproject.org/rpms/rubygem-unf.git /var/lib/mock/f45-build-35459-695/root/chroot_tmpdir/scmroot/rubygem-unf
Cloning into '/var/lib/mock/f45-build-35459-695/root/chroot_tmpdir/scmroot/rubygem-unf'...
$ git fetch origin 6ca73135053171bda342fb9dad3f8916721ee886:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-unf
 * [new ref]         6ca73135053171bda342fb9dad3f8916721ee886 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6ca7313 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild