$ git clone -n https://src.fedoraproject.org/rpms/xonsh.git /var/lib/mock/f40-build-2117250-50724/root/chroot_tmpdir/scmroot/xonsh
Cloning into '/var/lib/mock/f40-build-2117250-50724/root/chroot_tmpdir/scmroot/xonsh'...
$ git fetch origin e5159aca3fc68ef43770f0c2cd7176547896f366:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xonsh
 * [new ref]         e5159aca3fc68ef43770f0c2cd7176547896f366 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e5159ac Update to 0.14.1