I agree with taming, keeping the original files is always a good idea. The format may change in the future. I did have to revert a book because I processed it twice
. I also can't say about DRM. It may be different, I didn't look into that as there is a reason for it. I was just interested in having my own documents displayed properly and I like the was kepubs are handled by the device.
@murg: I wondered about the second number. It does seem to be a subsequence but I didn't analyze it and doesn't seem needed to get annotations working so I left it at that.
@mapline: The faster page turns are probably due to the rendering engine used for this format. For the naming when uploading with calibre you can take a look at
http://manual.calibre-ebook.com/gui.html#send-to-device and
http://manual.calibre-ebook.com/template_lang.html. The default in calibre is "{author_sort}/{title} - {authors}". You just have to change it to "{author_sort}/{title} - {authors}.kepub". But keep in mind that this will be applied to all documents you upload to your device.
The original Modify epub plugin can be found here
https://www.mobileread.com/forums/sho...d.php?t=154371 . I only added a function and a menu entry to be able to add the extra tags to a book. The main problem was that I also had to include the latest version of BeautifulSoup as the one packed in calibre is an older version and didn't have all the functions I needed. From what I've seen the plugin uses lxml instead of BeautifulSoup but I only had a couple of hours to figure out how to add those tagsand BeautifulSoup seemed the easier option. I suggest you ask on the Modify epub thread if someone could include this function and rewrite it using lxml as the you may want to update the plugin in the future and the logic involved is actually very simple.