[harshreality]

Is there epub-specific html markup you could add to changed words to indicate their original spelling? Like alt text for images, but in a span around a word? There's the html "title" attribute, of course, which would work (mouseover shows the title attribute's value), but that isn't semantically correct for the purpose.

[acabal]

No, there are too many things to track, but all of it is in the git history. Editorial changes have a commit message prefaced with [Editorial].