Improving documentation of Org Mode integration into Emacs.

[Karl Fogel]

I'd like to improve our in-tree documentation of how Org Mode 
integration into GNU Emacs works.

Many of us know from experience that Org Mode is maintained in a 
separate repository at git://git.sv.gnu.org/emacs/org-mode.git, 
and that it has its own project home site at https://orgmode.org/. 
But to a newcomer or an occasional contributor, this isn't 
obvious: they just see the sources in 'lisp/org/', looking like 
any other Lisp subdir in Emacs.

The fact that Org Mode is special is not clearly documented for 
those whose entry point is the Emacs sources.  While "orgmode.org" 
is mentioned in a header comment in, e.g., 'org.el', it's not 
prominent, and it's especially easy to miss because one often 
lands in the middle of a .el file via etags or grep or some other 
method that doesn't involve entering through the top.

And even for those who do happen to know that Org Mode is special, 
we can't tell from inspection exactly what 'lisp/org/' represents. 
Is it a release of Org Mode?  A regularly-updated clone of the 
upstream development sources?  Something else?

I finally found 
https://orgmode.org/worg/org-maintenance.html#org9ffe058, which 
describes how it works.

So I'd like to add some documentation in our tree, clarifying this 
situation for future searchers.  Most likely, this would be a 
brief mention in CONTRIBUTE, pointing to a new file 
lisp/org/README which would give more details and point to the 
above page.

Any objections / thoughts / suggestions about this, before I start 
on it?

Best regards,
-Karl

[2] https://list.orgmode.org/87czmcccrp.fsf@red-bean.com/T/#u