: Built on HTML5 , CSS3 , and JavaScript , allowing for advanced layouts and interactivity.

: Greatly improved support for non-Latin alphabets, vertical writing, and screen readers through the DAISY Consortium standards.

Whether you need converting a file or just a download link ? Key Issue - EPUB 3's coming of age

If you are interested in the technical standard mentioned in your search results, it is a modern format designed to make digital books more interactive and accessible. Key Features of EPUB 3