+ * Returns information about all interwiki prefixes, in the form of rows
+ * of the interwiki table. Each row may have the following keys:
+ *
+ * - iw_prefix: the prefix. Always present.
+ * - iw_url: the URL to use for linking, with $1 as a placeholder for the target page.
+ * Always present.
+ * - iw_api: the URL of the API. Optional.
+ * - iw_wikiid: the wiki ID (usually the database name for local wikis). Optional.
+ * - iw_local: whether the wiki is local, and the "magic redirect" mechanism should apply.
+ * Defaults to false.
+ * - iw_trans: whether "scary transclusion" is allowed for this site.
+ * Defaults to false.