$ git clone -n https://src.fedoraproject.org/rpms/htmlcxx.git /var/lib/mock/f45-build-13489-451/root/chroot_tmpdir/scmroot/htmlcxx
Cloning into '/var/lib/mock/f45-build-13489-451/root/chroot_tmpdir/scmroot/htmlcxx'...
$ git fetch origin bd5a480fed88de7ba957f119cc5440f0903f650a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/htmlcxx
 * [new ref]         bd5a480fed88de7ba957f119cc5440f0903f650a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at bd5a480 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild