Forgive the cross posting but I wanted to repeat what I found here:
This is a critical tool.
Adobe's version of "Alice in Wonderland", and "The Adventures of Sherlock Holmes" both are full of errors.
Even "EpubGuide-hxa7241.epub" has the wrong mine type and missing attributes in the toc.ncx file.
It will help, at the very least, software developers to better write reader software, and it will be invaluable to publishers and editors.
Could I make an open request to anyone more HTML savvy than myself - can the jar file have a HTML front end to make it a bit more user friendly (with a file selector and a text file output)?