I also have another tool I am working on, which I have tested the features so far:
https://github.com/geek1011/epubtool. It can pack, unpack, and validate epubs so far, and it may be useful when testing kepubify. I have tested it on Linux.
Example usage:
epubtool unpack /path/to/book.epub
epubtool pack /path/to/epub
epubtool validate /path/to/packed/book.epub
Sent from my XT1527 using Tapatalk