Similar to
AnonymousDonor, except that the applier of the label doesn't know or cannot reassuringly determine the authorship. In general, the author themselves will put
AnonymousDonor, while other parties may declare existing text from
UnknownDonor to avoid "putting words" in the original author's mouth. It may seem trivial to make such a distinction, but misunderstandings have a tendency to trigger flamewars.