$ git clone -n https://src.fedoraproject.org/rpms/rubygem-thor.git /var/lib/mock/f45-build-35380-695/root/chroot_tmpdir/scmroot/rubygem-thor
Cloning into '/var/lib/mock/f45-build-35380-695/root/chroot_tmpdir/scmroot/rubygem-thor'...
$ git fetch origin bfdc51b0d8398562b61321c18b9e3b87320e56c5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-thor
 * [new ref]         bfdc51b0d8398562b61321c18b9e3b87320e56c5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bfdc51b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild