The Calibre Editor by default directly modify the original file, without giving the option to back it up; having a backup copy is always handy, and I think that an option to automatically backup the file and work on a copy could be handy.
The
Modify epub plugin, used to make small midifications to ebooks, before applying any change create a backup copy named ORIGINAL_EPUB.
Is it possible to have the full fledged editor behave in the same way, if not by default, at least as an option?