Hi
Between basic EPUB2 and EPUB3 ((I mean having about the same features for both sides) there are differences, for exemple for writing some metadata.
There is one about
svg: If I insert a svg tag in an EPUB3 html file (it could be a wrapper svg for the cover, or any other svg tag inline within a html file) Epubcheck will recommend me to add
to the corresponding item definition in the .opf file (the "item" being the html file).
Once you know how to do, it's obvious how to proceed. Many users don't know. Would you consider proposing an automatic fix to this when we check the EPUB3?