add listing of fallback language to SiteInfo/General
I think it would be nice to know which language is the fallback language ($fallback in Message.php).
This information can be used e.g. by bots to know which language should by used on edit summary when there is no translation for the primary language.
I think it should by added to the gernal information part of Siteinfo.
I've created a patch which lists all fallback language as an array by requesting action=query&meta=siteinfo&siprop=general.