Server Buffer edits

[Harry Putnam <reader@newsguy.com>]

Is there an explanation somewhere as to what guidlines are in force
when editing a server.  Some are editable some are not.  Doesn't seem
to make any difference if a server has groups active or is open or
closed.

The ones that open for editing when pressing "e" do so regardless or
those conditions.  The ones that do not open, do so regardless of
those conditions too. 

The info "Server buffer" section doesn't seem to go into this aspect.

What differentiates an editable server from non-editable.

My server buffer has this break down:

edit       {nnfolder:archive} (opened)
edit       {nnml:n2m} (opened)

noedit     {nndir:~/News/agent/nntp/enews.newsguy.com/gnu/emacs/gnus/} (opened)
noedit     {nndir:~/spool/backup/} (opened)
noedit     {nndraft:} (opened)
noedit     {nnml:} (opened)
noedit     {nntp:enews.newsguy.com} (opened)