I use 7-Zip to remove fonts from ePub files (such as http://www.mobileread.com/forums/attachment.php?s=b36002a1818ccde176151cd39587c912&attachmentid=96434).
I can add files, but when I try to delete files I get an error.
If I change the extension to .zip, everything works fine.
Would it be possible to implement file deletion in .epub?
Many thanks for your help,