|
The .sdr is removed specifically when a book is deleted through the Kindle interface and ISN'T in your cloud. I assume Amazon doesn't want people to lose the notes/highlights/bookmarks on their sideloaded books unless they really want it gone.
If you delete a book using calibre, it cleans up after the book as well, removing the .sdr since calibre knows how to write generated .apnx's there.
|