In lujvo which involve the rafsi "-zil-", which place(s) get deleted? Is
it the first (unoccupied) one, or is it the last (unoccupied) one, or is
it purely vague (and potentially plural)? My interpretation is that it is
the last option, but it might be better to specify a hard rule. On the
other hand, we would need to have a general way of targeting alternative
but specific places for deletion in that case. Note that later sumti slots
will tend to be less useful and thus more likely to be deleted.

Also, which brivla is affected is not totally clear to me. I have some
natural interpretations, but I am not sure that they are actually
justified by any text. I need to review.