$ git clone -n https://src.fedoraproject.org/rpms/brewtarget.git /var/lib/mock/f40-build-2208842-52141/root/chroot_tmpdir/scmroot/brewtarget
Cloning into '/var/lib/mock/f40-build-2208842-52141/root/chroot_tmpdir/scmroot/brewtarget'...
$ git fetch origin f85be02d378d42d9356008bbab7f4d1e2982d6a2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/brewtarget
 * [new ref]         f85be02d378d42d9356008bbab7f4d1e2982d6a2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f85be02 Stop building for i686