$ git clone -n https://src.fedoraproject.org/rpms/rubygem-red-colors.git /var/lib/mock/f45-build-35229-694/root/chroot_tmpdir/scmroot/rubygem-red-colors
Cloning into '/var/lib/mock/f45-build-35229-694/root/chroot_tmpdir/scmroot/rubygem-red-colors'...
$ git fetch origin cbd09a646a352856d316272745a6b901b343a7ef:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-red-colors
 * [new ref]         cbd09a646a352856d316272745a6b901b343a7ef -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cbd09a6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild