Feature summary:
Please add functionality to export the book to a file (epub, pdf) from the Wikisource Index page. To be able to download all pages of the Page NS of this file (index).
Also need a notable "Download" button at the top of the Index page, like on the Main NS pages.

Benefits (why should this be implemented?):
The current functionality of the WS Export extension only works in the Main NS. And it needs the titles of the exported pages to be subpages.
For example, if this is a magazine that includes many works and poems of different authors and topics, then the pages should be called something like this: "A certain magazine/1905/Issue 5/Shakespeare's poem", "A certain magazine/1905/Issue 5/Einstein's article". But naming pages of works as subpages is not always possible, especially if the titles are long, and in many cases it is unacceptable. Each work has its own separate name in the main namespace.
Creating a page with a table of contents in the main namespace, which is a shortened duplicate of the Index page, where the table of contents and edition data is already located, is a waste of time and resources.
Often a collection may contain dozens of small works - stories, articles, or poems, one on each individual page. In modern times, no reader will waste time exporting each individual small work to a file, and then spend time moving them to their gadget. It is more convenient for readers to download the entire book/magazine, including all works.

The Table of Contents (TOC) can be taken from the Index page block of the same name and placed at the beginning of the exported file. If any of the included pages has a proofreaded TOC, then let it stay and exported in the same place in the page order. (The TOC on the Index page is usually rewritten by users in their own way, as are the TOCs in the Main NS. Whereas the proofreaded TOC is authentic to the edition and may differ.)