Amazon introduced the KF8 fork of Kindle files on the sly. Kindlegen was
producing KF8 files way before Amazon announced the new format. PG always used kindlegen to produce Kindle files out of epub. So we can say PG was producing KF8 files even before Amazon announced them. Just to remind people where "Amazon Kindle" is nowadays, K1, [Kindle first generation] K2, and DX are still looking for the old "super dumb" Mobi7 format, which basically tried to follow IE5 "conventions", if I remember right. Whereas all the newer Kindles now understand Mobi8 [KF8] which Marcello is saying is basically ADE. The older Kindles often pick up the paragraph problem where many "html" submitters to PG implement "belt, suspenders, and suspenders" -- setting top margin, bottom margin, and text indent [where only one of three really makes sense] resulting in the IE5 legacy of NOT merging top and bottom margins. The newer Kindles follow more recent "html" convention of merging top and bottom margins, but in turn tend to pick up more of the problems where "html" submitters made poor choices of left and right document margins selections on one or more sections of their books. These are typically not "epub" nor "mobi" problems but rather errors in coding the submitted "html" which one can easily see by changing the window size on one's html browser.