It allows the transclusion from other Wikisource domain (or another Wikimedia site); useful for multilingual books. Parameters (used at "iw_trans" function at MediaWiki:InterWikiTransclusion.js):

  1. The first is the ISO code of the language ("es" for Spanish, "fr" for French, etc.). For this multilingual Wikisource, it will be "old".
  2. The second is the title of the page on the other Wikisource.
  3. The third (optional) is the name of the other Wikimedia site (wikipedia, wiktionary, wikinews, wikibooks, wikiquote). Default is "wikisource".

Examples: