nnimap-list-pattern doesn't work?

[Carson Chittom <carson@wistly.net>]

I'm using Emacs 24, with the built-in Gnus.  Amongst other things, in
~/.gnus I have, following the manual,

(setq gnus-secondary-select-methods
      '((nnimap "Mailserver"
                (nnimap-address "mail.example.com")
                (nnimap-stream ssl)
                (nnimap-list-pattern ("INBOX" "Mail/*")))))

The nnimap-list-pattern appears to do pretty much nothing at all.  Which
means I probably am mistaken as to what it's doing.  My assumption,
based on the manual's sentence in section 6.5

      [nnimap-list-pattern] is used when the server has very many
      mailboxes and you're only interested in a few--some servers export
      your home directory via IMAP, you'll probably want to limit the
      mailboxes to those in '~/Mail/*' then.

was that this meant that Gnus simply didn't worry about anything that
wasn't specifically listed.  But going to the server buffer and selecting
this mailserver, the first things listed are all my dotfiles, followed
by the contents of ~/News and everything else.

So what does nnimap-list-pattern actually do?  Control what's listed in
the summary buffer?

(This came up while I was trying to decrease my startup time--what I
really wanted to do was set gnus-check-new-newsgroups to nil.)