Got me, you have to go hunting around and find out. I have no way to tell you what's on your box, but I can tell you the entries aren't from SpamAssassin itself. ;)
I believe that it is a bug in SA 3.0. This is a fresh installation of SA, no blacklists have been created and the e-mail address was previously unknown.
Having searched back through the archives there are a couple of other reports of this 'phenomenon'.
Mike.
