but ultimately the real reason
is that the arcane and unpopular nature of the texts I'm
interested in uploading have made me persona non grata
at German Wikisource.
I think that's awfully sad! - But, to the original question, can someone tell me where the language code, whether en or mul/und part would appear at all? I don't understand what is being discussed. When I look at current interwiki links on WD, I see they have their language code next to it - surely the Multilingual Wikisource entries should not have "en" - is that the question here?