-@item gnus-sum-thread-tree-single-leaf
-@vindex gnus-sum-thread-tree-single-leaf
-Used for a leaf without brothers. The default is @samp{\-> }
-
-@end table
-
-@item T
-Nothing if the article is a root and lots of spaces if it isn't (it
-pushes everything after it off the screen).
-@item [
-Opening bracket, which is normally @samp{[}, but can also be @samp{<}
-for adopted articles (@pxref{Customizing Threading}).
-@item ]
-Closing bracket, which is normally @samp{]}, but can also be @samp{>}
-for adopted articles.
-@item >
-One space for each thread level.
-@item <
-Twenty minus thread level spaces.
-@item U
-Unread. @xref{Read Articles}.
-
-@item R
-This misleadingly named specifier is the @dfn{secondary mark}. This
-mark will say whether the article has been replied to, has been cached,
-or has been saved. @xref{Other Marks}.
-
-@item i
-Score as a number (@pxref{Scoring}).
-@item z
-@vindex gnus-summary-zcore-fuzz
-Zcore, @samp{+} if above the default level and @samp{-} if below the
-default level. If the difference between
-@code{gnus-summary-default-score} and the score is less than
-@code{gnus-summary-zcore-fuzz}, this spec will not be used.
-@item V
-Total thread score.
-@item x
-@code{Xref}.
-@item D
-@code{Date}.
-@item d
-The @code{Date} in @code{DD-MMM} format.
-@item o
-The @code{Date} in @var{YYYYMMDD}@code{T}@var{HHMMSS} format.
-@item M
-@code{Message-ID}.
-@item r
-@code{References}.
-@item t
-Number of articles in the current sub-thread. Using this spec will slow
-down summary buffer generation somewhat.
-@item e
-An @samp{=} (@code{gnus-not-empty-thread-mark}) will be displayed if the
-article has any children.
-@item P
-The line number.
-@item O
-Download mark.
-@item *
-Desired cursor position (instead of after first colon).
-@item &user-date;
-Age sensitive date format. Various date format is defined in
-@code{gnus-user-date-format-alist}.
-@item u
-User defined specifier. The next character in the format string should
-be a letter. Gnus will call the function
-@code{gnus-user-format-function-@var{x}}, where @var{x} is the letter
-following @samp{%u}. The function will be passed the current header as
-argument. The function should return a string, which will be inserted
-into the summary just like information from any other summary specifier.
-@end table
-
-Text between @samp{%(} and @samp{%)} will be highlighted with
-@code{gnus-mouse-face} when the mouse point is placed inside the area.
-There can only be one such area.
-
-The @samp{%U} (status), @samp{%R} (replied) and @samp{%z} (zcore) specs
-have to be handled with care. For reasons of efficiency, Gnus will
-compute what column these characters will end up in, and ``hard-code''
-that. This means that it is invalid to have these specs after a
-variable-length spec. Well, you might not be arrested, but your summary
-buffer will look strange, which is bad enough.
-
-The smart choice is to have these specs as far to the left as possible.
-(Isn't that the case with everything, though? But I digress.)
-
-This restriction may disappear in later versions of Gnus.
-
-
-@node To From Newsgroups
-@subsection To From Newsgroups
-@cindex To
-@cindex Newsgroups
-
-In some groups (particularly in archive groups), the @code{From} header
-isn't very interesting, since all the articles there are written by
-you. To display the information in the @code{To} or @code{Newsgroups}
-headers instead, you need to decide three things: What information to
-gather; where to display it; and when to display it.
-
-@enumerate
-@item
-@vindex gnus-extra-headers
-The reading of extra header information is controlled by the
-@code{gnus-extra-headers}. This is a list of header symbols. For
-instance:
-
-@lisp
-(setq gnus-extra-headers
- '(To Newsgroups X-Newsreader))
-@end lisp
-
-This will result in Gnus trying to obtain these three headers, and
-storing it in header structures for later easy retrieval.
-
-@item
-@findex gnus-extra-header
-The value of these extra headers can be accessed via the
-@code{gnus-extra-header} function. Here's a format line spec that will
-access the @code{X-Newsreader} header:
-
-@example
-"%~(form (gnus-extra-header 'X-Newsreader))@@"
-@end example
-
-@item
-@vindex gnus-ignored-from-addresses
-The @code{gnus-ignored-from-addresses} variable says when the @samp{%f}
-summary line spec returns the @code{To}, @code{Newsreader} or
-@code{From} header. If this regexp matches the contents of the
-@code{From} header, the value of the @code{To} or @code{Newsreader}
-headers are used instead.
-
-To distinguish regular articles from those where the @code{From} field
-has been swapped, a string is prefixed to the @code{To} or
-@code{Newsgroups} header in the summary line. By default the string is
-@samp{-> } for @code{To} and @samp{=> } for @code{Newsgroups}, you can
-customize these strings with @code{gnus-summary-to-prefix} and
-@code{gnus-summary-newsgroup-prefix}.
-
-@end enumerate
-
-@vindex nnmail-extra-headers
-A related variable is @code{nnmail-extra-headers}, which controls when
-to include extra headers when generating overview (@acronym{NOV}) files.
-If you have old overview files, you should regenerate them after
-changing this variable, by entering the server buffer using @kbd{^},
-and then @kbd{g} on the appropriate mail server (e.g. nnml) to cause
-regeneration.
-
-@vindex gnus-summary-line-format
-You also have to instruct Gnus to display the data by changing the
-@code{%n} spec to the @code{%f} spec in the
-@code{gnus-summary-line-format} variable.
-
-In summary, you'd typically put something like the following in
-@file{~/.gnus.el}:
-
-@lisp
-(setq gnus-extra-headers
- '(To Newsgroups))
-(setq nnmail-extra-headers gnus-extra-headers)
-(setq gnus-summary-line-format
- "%U%R%z%I%(%[%4L: %-23,23f%]%) %s\n")
-(setq gnus-ignored-from-addresses
- "Your Name Here")
-@end lisp
-
-(The values listed above are the default values in Gnus. Alter them
-to fit your needs.)
-
-A note for news server administrators, or for users who wish to try to
-convince their news server administrator to provide some additional
-support:
-
-The above is mostly useful for mail groups, where you have control over
-the @acronym{NOV} files that are created. However, if you can persuade your
-nntp admin to add (in the usual implementation, notably INN):
-
-@example
-Newsgroups:full
-@end example
-
-to the end of her @file{overview.fmt} file, then you can use that just
-as you would the extra headers from the mail groups.
-
-
-@node Summary Buffer Mode Line
-@subsection Summary Buffer Mode Line
-
-@vindex gnus-summary-mode-line-format
-You can also change the format of the summary mode bar (@pxref{Mode Line
-Formatting}). Set @code{gnus-summary-mode-line-format} to whatever you
-like. The default is @samp{Gnus: %%b [%A] %Z}.
-
-Here are the elements you can play with:
-
-@table @samp
-@item G
-Group name.
-@item p
-Unprefixed group name.
-@item A
-Current article number.
-@item z
-Current article score.
-@item V
-Gnus version.
-@item U
-Number of unread articles in this group.
-@item e
-Number of unread articles in this group that aren't displayed in the
-summary buffer.
-@item Z
-A string with the number of unread and unselected articles represented
-either as @samp{<%U(+%e) more>} if there are both unread and unselected
-articles, and just as @samp{<%U more>} if there are just unread articles
-and no unselected ones.
-@item g
-Shortish group name. For instance, @samp{rec.arts.anime} will be
-shortened to @samp{r.a.anime}.
-@item S
-Subject of the current article.
-@item u
-User-defined spec (@pxref{User-Defined Specs}).
-@item s
-Name of the current score file (@pxref{Scoring}).
-@item d
-Number of dormant articles (@pxref{Unread Articles}).
-@item t
-Number of ticked articles (@pxref{Unread Articles}).
-@item r
-Number of articles that have been marked as read in this session.
-@item E
-Number of articles expunged by the score files.
-@end table
-
-
-@node Summary Highlighting
-@subsection Summary Highlighting
-
-@table @code
-
-@item gnus-visual-mark-article-hook
-@vindex gnus-visual-mark-article-hook
-This hook is run after selecting an article. It is meant to be used for
-highlighting the article in some way. It is not run if
-@code{gnus-visual} is @code{nil}.
-
-@item gnus-summary-update-hook
-@vindex gnus-summary-update-hook
-This hook is called when a summary line is changed. It is not run if
-@code{gnus-visual} is @code{nil}.
-
-@item gnus-summary-selected-face
-@vindex gnus-summary-selected-face
-This is the face (or @dfn{font} as some people call it) used to
-highlight the current article in the summary buffer.
-
-@item gnus-summary-highlight
-@vindex gnus-summary-highlight
-Summary lines are highlighted according to this variable, which is a
-list where the elements are of the format @code{(@var{form}
-. @var{face})}. If you would, for instance, like ticked articles to be
-italic and high-scored articles to be bold, you could set this variable
-to something like
-@lisp
-(((eq mark gnus-ticked-mark) . italic)
- ((> score default) . bold))
-@end lisp
-As you may have guessed, if @var{form} returns a non-@code{nil} value,
-@var{face} will be applied to the line.
-@end table
-
-
-@node Summary Maneuvering
-@section Summary Maneuvering
-@cindex summary movement
-
-All the straight movement commands understand the numeric prefix and
-behave pretty much as you'd expect.
-
-None of these commands select articles.
-
-@table @kbd
-@item G M-n
-@itemx M-n
-@kindex M-n (Summary)
-@kindex G M-n (Summary)
-@findex gnus-summary-next-unread-subject
-Go to the next summary line of an unread article
-(@code{gnus-summary-next-unread-subject}).
-
-@item G M-p
-@itemx M-p
-@kindex M-p (Summary)
-@kindex G M-p (Summary)
-@findex gnus-summary-prev-unread-subject
-Go to the previous summary line of an unread article
-(@code{gnus-summary-prev-unread-subject}).
-
-@item G g
-@kindex G g (Summary)
-@findex gnus-summary-goto-subject
-Ask for an article number and then go to the summary line of that article
-without displaying the article (@code{gnus-summary-goto-subject}).
-@end table
-
-If Gnus asks you to press a key to confirm going to the next group, you
-can use the @kbd{C-n} and @kbd{C-p} keys to move around the group
-buffer, searching for the next group to read without actually returning
-to the group buffer.
-
-Variables related to summary movement:
-
-@table @code
-
-@vindex gnus-auto-select-next
-@item gnus-auto-select-next
-If you issue one of the movement commands (like @kbd{n}) and there are
-no more unread articles after the current one, Gnus will offer to go to
-the next group. If this variable is @code{t} and the next group is
-empty, Gnus will exit summary mode and return to the group buffer. If
-this variable is neither @code{t} nor @code{nil}, Gnus will select the
-next group with unread articles. As a special case, if this variable
-is @code{quietly}, Gnus will select the next group without asking for
-confirmation. If this variable is @code{almost-quietly}, the same
-will happen only if you are located on the last article in the group.
-Finally, if this variable is @code{slightly-quietly}, the @kbd{Z n}
-command will go to the next group without confirmation. Also
-@pxref{Group Levels}.
-
-@item gnus-auto-select-same
-@vindex gnus-auto-select-same
-If non-@code{nil}, all the movement commands will try to go to the next
-article with the same subject as the current. (@dfn{Same} here might
-mean @dfn{roughly equal}. See @code{gnus-summary-gather-subject-limit}
-for details (@pxref{Customizing Threading}).) If there are no more
-articles with the same subject, go to the first unread article.
-
-This variable is not particularly useful if you use a threaded display.