[Mazarin07]

Originally Posted by Doitsu

@Mazarin07 The role and data-* attributes were introduced in the HTML5 specs. I.e., they can only be used in epub3 books.
A relatively easy fix would be to convert your epub2 book to an epub3 book with KevinH's ePub3-itizer plugin.

Thank you, this plugin of KevinH's worked fine. I am not sure if epub3 files are accepted by my PocketBook Basic reader, but will create a separate epub2 file for it if needed.