[tomsem]

I would just like to point out that there are at least 3 distinct KFX 'formats': Kindle (newer ones only), Fire/Android (which may or may not be the same), iOS. These are the platforms which currently support 'advanced typography'. If and when they roll AT out to Windows, Windows 10, Windows mobile, Mac OS, expect to see more 'formats'. 'Format' isn't the word I'd use for this. 'KFX container' might be better, as long as it is understood that it differs from platform to platform and not something portable between them.

While I think there is a strong probability that AT books will remain undecode-able from the containers delivered wirelessly, I would not expect the download from Manage Your Content and Devices to change, unless they add yet another format and create tools to generate that. 'Kindle Format' is what the various Amazon publishing tools generate, also what one can download from MYCAD for side-loading, and not what lands on the device wirelessly.

'KFX' just represents the latest development in a series of features which are provided by the reading ecosystem, and not inherent in the original content. Everything from annotations to xray to page numbers, some features of enhanced typography and continuing with Word Runner. It represents a break only in the sense that prior to this, there was something downloaded to the Kindle that you could pull off possibly 'disinfect' and convert to something else. Have we ever been able to do that with the Fire or mobile apps? Only with the desktop apps and Kindles, right?

Kobo's 'kepub' is similar in intent, though not in implementation details. Google inserts a bunch of tagging into the PDF and ePub files to enable switching between reflowable and original pages in the reading apps and whatever container exists on device is nothing like an ePub/PDF file: it's probably some HTML blob (you can start reading before it has downloaded completely). iBooks and Nook platforms seem to be the only major platforms where what the content downloaded wirelessly bears some resemblance to the ePub file the publisher submitted (and that's just a guess).