Amazon support for EPUB3 ???

Hello CG members,

I think there is an enormous gap between the news <https://www.theverge.com/2022/5/2/23053408/amazon-epub-kindle-ereader-file-format-kf8> that Amazon is supporting EPUB3 and the reality of what support is there.

A recently published valid epub3 fully accessible FXL book from our small press, served through an aggregator, is being rendered essentially as ‘garbage’ by the Kindle app.

There is no support for SVG format. There are several diagrams in the book which, for file-size considerations were built in SVG. Adding fallback .png files would considerably increase book size.
Many of the CSS styles (such as 'list-style-type: none’) are ignored
The FXL format is turned into a flowable book, breaking book narrative continuity
The ‘hidden’ embedded image description text is made visible (also CSS clip styles ignored)
The CSS style positioning on image description links is ignored
CSS line-height and padding/margin on headings are ignored

Essentially, if you want to make a book that is not merely a ‘wall of text’ but has design built in to provide readability affordances—you cannot rely on Amazon to give a good result.

After all the years, effort and work by members in development of this specification, I personally am affronted that Amazon—such a huge player in the market—consistently breaks the model that is set out and is currently well delivered by Apple, Vital Source Bookshelf and Thorium. 

Amazon: for shame!

Ruth Tait