We found this e-mail address from the public Google search results.

Can someone please explain to me how spamming public lists is somehow compatible with Google's stated 'don't be evil' ethos? freedesktop@l.fd.o wasn't the only list to get hit. Very disconcerting.

So, dear Google,
What gives?
Daniel

Update: Yes, I checked the headers, it's definitely Google:
Received: from smtp-out.google.com (smtp-out.google.com [216.239.45.12])
by gabe.freedesktop.org (Postfix) with ESMTP id 8EA189E72E
for <freedesktop@freedesktop.org>; Mon, 14 Aug 2006 16:53:29 -0700 (PDT)

Update #2: No, it wasn't a joe-job. And hopefully that'll be the last one they send.