About [[MediaWiki:Apihelp-sitematrix-description/en]]

There are two different "code"s listed in the API: the first refers to the ISO 639 code of the project. The second refers to the project suffix ("wiki", "wikiquote" and so forth). It's definitely confusing (I created T100459) -- I'm not sure what this is supposed to really say, as the "language code + project code" it describes is actually the "dbname" field.