KFX is a proprietary ebook file format developed by Amazon for use on Kindle devices and apps. It's a more advanced format than the older AZW3 (Kindle Format 8) and offers several improvements, including enhanced typography, better image handling, and support for more complex layouts. KFX files often incorporate features like enhanced typesetting, which aims to provide a more visually appealing and readable experience. This includes features like hyphenation, kerning, and ligatures, which are designed to improve the overall aesthetics of the text. The format also supports higher-resolution images and more sophisticated page layouts, allowing for richer and more visually engaging ebooks. KFX files are typically DRM-protected, meaning they can only be opened on authorized Kindle devices or apps associated with the Amazon account that purchased the ebook. While KFX offers a superior reading experience, it's important to note that it's a closed format, limiting its use to the Amazon ecosystem.