Topic Variables
---------------

   Now, if you select a topic, if will fold/unfold that topic, which is
really neat, I think.

   The topic lines themselves are created according to the
`gnus-topic-line-format' variable.  See Formatting Variables.
Elements allowed are:

`i'
     Indentation.

`n'
     Topic name.

`v'
     Visibility.

`l'
     Level.

`g'
     Number of groups in the topic.

`a'
     Number of unread articles in the topic.

`A'
     Number of unread articles in the topic and all its subtopics.

   Each sub-topic (and the groups in the sub-topics) will be indented
with `gnus-topic-indent-level' times the topic level number of spaces.
The default is `2'.

   `gnus-topic-mode-hook' is called in topic minor mode buffers.