Beyond just marking up an e-book, are there any devices that would also allow you to edit the file itself?
I doubt there is one since that would feel rather clumsy. If it is about editing the epub in general, you might like calibre. It is open source software intended for library management but comes with an epub editor.
Thank you. Yeah, I like to whittle down the text to the essential points as I read (this is with non-fiction). On an ipad, i open up the book in OnlyOffice to do this.
If I markup up the book instead (highlights, underlining and so forth), what happens to all of that when you open the book up in Calibre? Does it show the markups?
I think it depends on the eReader, but mine creates a txt file with all highlighted sections. I assume others behave similarly and store annotations outside the actual epub file.
If there are Android apps that do so, you can use an Android reader. I know you can edit PDFs, not sure about epubs.