[mhendu]

okay, so EMM writes these multiple tags,
when looking at the NFO specification at http://kodi.wiki/view/NFO_files/Movies there isn't even a certification tag mentioned..

@Karellen could you tell us, what Kodi exactly supports? thx

 I'll defer to @Karellen but per this page there is no certification field in Kodi's database, nor can I find one when browsing via SQL. The mpaa field is just a text field and can contain multiple values, though. The use case I'm describing is that in many cases movies are not rated by the MPAA - for many independent productions, short films, etc., the distributor doesn't bother paying the fee to have the MPAA rate the movie, and there are other titles that don't get distributed in the US that would never receive a rating. If the field only contains ratings for one country and ignores ratings for every other country then outside of the more popular movies that get released everywhere there will be gaps in certifications, so any filters for certifications would either end up including a lot of inappropriate content or excluding a lot of appropriate content, unless I go in and manually assign fake MPAA ratings to movies that are not rated by the MPAA.

http://kodi.wiki/view/databases