Amazon has discontinued KindleGen.
KindleGen is no longer available for download according to https://t.co/0TEAFg6h1Y
— Dan Rodney (@danrodneytweets) August 25, 2020
I checked the page in question, and he is correct. Amazon has removed the KindleGen download links and replaced them with a notice which reads:
KindleGen is no longer available for download. Please use Kindle Previewer to convert, preview, and validate your eBooks. Kindle Previewer provides the same functionality of KindleGen and, in addition, provides:
- Latest Kindle Conversion software that provides up-to-date validation for Enhanced Typesetting books (currently available for books in all languages except Simplified Chinese, Japanese, and Russian).
- Choice of using in Graphical User Interface (GUI) for a visual inspection of your book, or, Command Line Interface (CLI) mode for bulk validation.
- Faster preview and validation with features like thumbnails, auto-previews, and filters for pages with images, tables, drop caps, and links.
KindleGen was a command-line tool for creating Kindle ebooks. I beleive it launched around 2009, when it was a niche tool which was overshadowed by existing tools such as Mobipocket Creator. It was repeatedly updated over the years, but I don’t think it ever lost its status as a niche tool (there were always dozens of tools which could make Kindle ebooks).
I can’t tell you the last time I used KindleGen; I think it would have to be when I tested it to report on support for Russian. (This was all the way back in 2013!) I never found much use for the tool, but I understand that some publishers had integrated KindleGen into their production process. (Although I am not sure how many did; back when I paid more attention to this, I usually heard calibre mentioned instead.)