Not all//As a Wikisource communities want the same EPUBuser, PDFI want the download links in the sidebar to be customizable, and MOBI export links, so this list should be customizable on-wiki.so each wiki can have choose the UX that best suits their user's needs.//
As suggested at T256392#6753267.**Background:** In the process of migrating the WSExport gadget to the Wikisource extension, we received the following comment in T256392#6753267: "Have you considered adding a target = "_blank" attribute to the "Other formats" link so as not to "lose" the Wikisource page visitor? And ... do you consider selecting (configuring) a set of formats (links) for a given wiki?" In other words, not all Wikisource communities want the same EPUB, PDF, and MOBI export links, so the list should be customizable on-wiki.
* Make the download sidebar links customizable in Wikisource be customizable