I noticed a lack of an ePub generation library for .NET and decided to make one. I
thought that I was creating the final file properly, and Calibre was able to open and display it without any issues, but my Kindle won't read it, and the online ePub validators I tried just mostly hang without showing any useful errors.
I hope that perhaps someone more knowledgable about the format would be able to dissect what I generated and point me toward's what's wrong.
The generated ebook is attached to the post, and in case you don't trust random files downloaded from the internet, you can
find the source code of the generator here and run the
Demo project (requires .NET 8 SDK) to generate the exact same file I attached here.