which gnus files used to hold gnus state? (for manual)

[John Owens <jowens@ece.ucdavis.edu>]

I'd like to get a list of the files used to hold gnus state. This is
for potential inclusion in the manual (after discussion with Lars)
and would be important for users who are interested in synching the
gnus state of two machines (say, a laptop and a desktop).

I think this should be done in three parts and I hope gnus developers
can specify the relevant files for each of the parts. Also, the
default location for these files should be specified, and also the
gnus variables that can be used to change the defaults.

(I'm also putting some questions in - if you can answer my questions
I'd certainly appreciate it.)

1) general gnus state files that apply to any backend - .newsrc,    
.newsrc.eld, .emacs, .gnus. Is that the complete list? This could go
in manual section 1.8, "Startup Files".

2) gnus state files that apply to each backend. I am particularly 
concerned with nnimap, but I'm not sure there are any state files in
gnus that are associated with it (?) because maybe the imap server
keeps track of that internally? Evidently nnmail uses .nnmail-cache?
 
I'm aware there are News and Mail folders but I'm not sure what is 
supposed to live in them. How does this interact with nnimap - where 
are imap folders located in the directory structure and how does this 
work with gnus? 

This could go in section 6.3 where the backends are discussed.

3) gnus state files that apply to the Agent. Are there any?
(~/News/agent should contain ... ?) How about the cache? Where do
cached files live? (~/News/cache, but what files?) If I delete all the
cached files will they be refetched by the Agent? I'm, again,
particularly concerned with the imap interaction with the agent, and
want to know how files work with it. (Ideally I can have
semi-up-to-date IMAP mail folders on my laptop and can work with
those, and when I plug in they will be auto-updated manually? or
automatically?)

This could go in section 6.8 which deals with the Agent.

The overall goal would be to know exactly what files to sync if I want
to mirror my gnus setup on computer B from computer A. Hopefully in
the next generation of gnus there will be a list of state-containing
files and an automated way to sync them (gnus-sync-state-files with a
configurable sync command like "rsync -e ssh ..."). This could be
useful for users who use a laptop and want to sync before going on
the road.

JDO