I'm not sure where this post should go, but I've put it in the ePub forum because I'm seeking comment from people who are familiar with ePub formatting. I apologise in advance to the moderator if it needs to be moved.
The background is that there there is a thread in another forum which has died out, at
https://www.mobileread.com/forums/sho...d.php?t=255794
dealing with the fact that there are several ebooks on the Kobo site which are known to have been taken from the MobileRead library. I accept of course that the main text of these ebooks is in the Public Domain, even if the person who uploaded the ebook has taken great trouble to correct typos and so on.
And ePub ebooks are not just text files. There are the CSS, the content.opf file and the toc.ncx file, without which the ePub won't work or be readable. And many of us spend a great deal of time researching and writing our own original material to go in the description section of the content.opf file.
So, at last, my question: Is the material we put into the description area of the content.opf file copyright? If so, is there a minimal amount of of material to make it copyright?
Can anyone point me to references where this question is addressed?