I'm completely confused by something.

I'm using nnmail-split-fancy and gnus-registry-split-fancy-with-parent:

(require 'gnus-registry)

(setq gnus-registry-max-entries 5000
      gnus-registry-use-long-group-names t)

(setq nnmail-split-fancy-with-parent-ignore-groups
      '("spam.missed"
	"archive\\..*"))

(gnus-registry-initialize)

(setq nnmail-split-fancy
      '(|    ("X-DSPAM-Result" "Spam" "spam.caught")
       (|    ("X-SPAM-Charset" "yes.*" "spam.missed")
       (& (| (: gnus-registry-split-fancy-with-parent)
	     ("sender" "ubuntu-announce.*@lists\.ubuntu\.com" "ubuntu.announce")
	     ("sender" "ubuntu-users.*@lists\.ubuntu\.com" "ubuntu.users")
             ...)))))

I have a message:

  From: Norman Walsh <ndw@nwalsh.com>
  To: tag@w3.org
  Subject: XML 2.0
  X-Draft-From: ("w3c.member.tag")
  BCC: normanwalsh+bcc@gmail.com
  X-URL: http://nwalsh.com/
  X-Countdown: T-minus 47 weeks, 5 days, 17 hours, 2 minutes, 42 seconds
  Date: Wed, 20 Feb 2008 13:58:25 -0500
  Message-ID: <m2wsozqwtq.fsf@nwalsh.com>
  User-Agent: Gnus/5.110007 (No Gnus v0.7) Emacs/22.1.50 (darwin)
  MIME-Version: 1.0
  Content-Type: multipart/signed; boundary="=-=-=";
  	micalg=pgp-sha1; protocol="application/pgp-signature"
  Lines: 28
  Xref: nwalsh.com w3c.member.tag:6082

  ...

If I put the cursor in that message and run 
(gnus-registry-split-fancy-with-parent), it returns "nil", as I'd expect.

But if I do B t, I get:

(: gnus-registry-split-fancy-with-parent)
"misc"
(: nwalsh-incoming-group)
"archive.2008-02"

which I find totally baffling. Where is that 'misc' coming from?

Note that gnus-registry-track-extra is nil.

Any clues you can provide would be most helpful.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | When it is not necessary to make a
http://nwalsh.com/            | decision, it is necessary not to make a
                              | decision.--Lord Falkland