[MetaCRS] IGNF Projection catalog?

[Christopher Schmidt]

Hi,

I see that proj4js has a catalog for the IGNF projections:

  http://trac.osgeo.org/proj4js/browser/trunk/tools/catalogues/IGNF

I've googled, and found a couple places where these codes appear to
possibly come from:
  
  http://www.geoportail.fr/partage/Professionnel/RIG/RIG.xml
  http://svn.osgeo.org/gdal/trunk/gdal/ogr/ogrsf_frmts/geoconcept/geoconcept_syscoord.c

and the code mentions that:

 " The following information came from GEO CONCEPT PROJECTION files"

There is also:
  http://lambert93.ign.fr/index.php?id=28

Which is in French, but mentions "+init=IGNF:LAMBE +to
+init=IGNF:LAMB93", which makes me think it might be related.   

Can anyone point to the canonical source for this data? is it the
RIG.xml, and is there a process used to convert these to WKT? (Or is
proj4 the canonical string format?)
 
Regards, 
-- 
Christopher Schmidt
MetaCarta