$ git clone -n https://src.fedoraproject.org/rpms/emacs.git /var/lib/mock/f45-build-8031-372/root/chroot_tmpdir/scmroot/emacs
Cloning into '/var/lib/mock/f45-build-8031-372/root/chroot_tmpdir/scmroot/emacs'...
$ git fetch origin 446e0b422959603cd128cce47cfb3e75bc23fb3c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/emacs
 * [new ref]         446e0b422959603cd128cce47cfb3e75bc23fb3c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 446e0b4 Update to version 31.1.