gh-118689: fix ePub build

[methane]

• Issue: ePub error reported at docs@python.org #118689

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📚 Documentation preview 📚: https://cpython-previews--118690.org.readthedocs.build/

[methane]

glossary.json caused unknown mimetype error. I don't know when this error starts. Maybe, recent Sphinx become more strict?

#116966 introduced JavaScript in ePub. This should be backported into 3.12.

#109438 introduced duplicated ToC error. This is Python 3.13 only issue.

[methane]

With this fix, I can open the epub file with Books.app in macOS.

There are many other errors reported by epubcheck.
Some of them are caused by opengraph.
wpilibsuite/sphinxext-opengraph#120

[methane]

Another issue:
readthedocs/sphinx-notfound-page#230

[methane]

Remaining errors:

$ epubcheck --locale en-US build/epub/Python.epub 2>python-epub-errors.txt

https://gist.github.com/methane/03a569934bec14a2b4b2a783f96d01b3

[methane]

I found epub_use_index option so I use it to disable index.
Index page has been broken from start. When I show index page in Books.app, the app show only erro and I can not use the book.
Since index pages are very inaccessible (no link from toc), no one care it.

[hugovk]

Thank you for the fixes.

With this fix, I can open the epub file with Books.app in macOS.

Same here 👍

There are many other errors reported by epubcheck.

This sounds like something we should aim to add to the CI, even if we start with a subset of passing checks.

Thanks also for opening issues in the extensions.

[miss-islington-app]

Thanks @methane for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-118889 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-118890 is a backport of this pull request to the 3.12 branch.