It would be really nice if mp3tag supported CD tags i.e. Red Book Audio CD TEXT in e.g. .iso files.
Any chance?
Nope.
May I ask why? CD is a fairly common format! 
Sure 
But I want to focus on other parts of Mp3tag. Implementing support for Audio CDs would require much of the free time I have for developing Mp3tag.
Fair enough. I guess it's not the simple library module drop-in I'd hoped!