Having run a check for straightforward spam, I now find that there's a site editing and reposting non-spam posts. An example of the changed headers follows:
Original post headers: > > From c...@seckford.org Sun Feb 11 23:23:22 2018 > Path: > eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail > Message-ID: <4sd3le-ct4....@tanner.seckford.org> > From: C W Rose <c...@seckford.org> > Newsgroups: comp.lang.python > Subject: Spam levels. > Date: Sat, 10 Feb 2018 14:57:40 +0000 > Lines: 49 > Organization: None > Injection-Info: reader02.eternal-september.org; > posting-host="208e6410f66c7dd789dea67159b51bb7"; > logging-data="6406"; mail-complaints-to="ab...@eternal-september.org"; > posting-account="U2FsdGVkX18su+yG7dqCpnqChqoPIY0JNXRwgNWzvcs=" > User-Agent: tin/2.0.1-20111224 ("Achenvoir") (UNIX) (Linux/3.10.79-gentoo-1 > (i686)) > Cancel-Lock: sha1:H7zOidR0ivbNjqiWUB6DSoMMYu8= > Xref: tanner.seckford.org comp.lang.python:139461 > Repost headers: > > From C Sun Feb 11 23:22:54 2018 > Path: > eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!aioe.org!news.bbs.geek.nz!.POSTED.agency.bbs.geek.nz!not-for-mail > Message-ID: <847574...@f38.n261.z1.binkp.net> > From: C W Rose <c...@seckford.org> (C W Rose) > Newsgroups: comp.lang.python > Subject: Spam levels. > Date: Sat, 10 Feb 2018 14:57:40 +1200 > Organization: fsxNet Usenet Gateway | bbs.nz/#fsxNet > Mime-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > Injection-Info: news.bbs.geek.nz; > posting-host="M6YmRdZYyc42DJk0lNlt/X4dpP4dzvceBNabSmESN3E"; > logging-data="24378"; mail-complaints-to="ab...@news.bbs.geek.nz" > User-Agent: VSoup v1.2.9.47Beta [95/NT] > X-MailConverter: SoupGate-Win32 v1.05 > X-Comment-To: All > Xref: tanner.seckford.org comp.lang.python:139479 Looking at my current comp.lang.python news spool, 182 out of 683 messages have been reposted by news.bbs.geek.nz; I haven't checked if they are all duplicates. The reformatting of the body of message is to date trivial, just a reduction in line length. This may be the result of a misconfigured spam filter, or an actual spam attack; anyway, I've now filtered news.bbs.geek.nz from my feed. Will -- "When we look around us, this is what we find, The hope that springs eternal, springs right up your behind." -- Ian Dury -- https://mail.python.org/mailman/listinfo/python-list