Actually, no, `edition_id` is actually the slug of the document `edition_class.published_as` does the magic that finds the document and returns the published edition. As we're previewing the HTML version of presumably a draft edition, I figured it made more sense to load the most recent edition. In reality, I think it makes little material difference - the edition is only used to generate a link back to it in html version view. I'll rename `edition_id` to reflect what it actually is.