$ git clone -n https://src.fedoraproject.org/rpms/rubygem-rdtool.git /var/lib/mock/f45-build-35219-694/root/chroot_tmpdir/scmroot/rubygem-rdtool
Cloning into '/var/lib/mock/f45-build-35219-694/root/chroot_tmpdir/scmroot/rubygem-rdtool'...
$ git fetch origin a173cdef6308b59dc5b3887c823ce039ebb0850f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-rdtool
 * [new ref]         a173cdef6308b59dc5b3887c823ce039ebb0850f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a173cde Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild