$ git clone -n https://src.fedoraproject.org/rpms/emacs-s.git /var/lib/mock/f45-build-8123-377/root/chroot_tmpdir/scmroot/emacs-s
Cloning into '/var/lib/mock/f45-build-8123-377/root/chroot_tmpdir/scmroot/emacs-s'...
$ git fetch origin db9ab19d5a5652509757316345a6c1097adcb0b8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/emacs-s
 * [new ref]         db9ab19d5a5652509757316345a6c1097adcb0b8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at db9ab19 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild