Validator gives error on “href” attribute in manifest item for remote resources
I know that you don't guarantee that an EPUB produced by Calibre is valid (http://
Remote audio and video resources have to be included in the manifest as a separate item element, which according to the epub3 specifications require a “href” attribute.
The validator, however, marks the entry with the use of “href“ as an error while the use of “src“ seems to be valid. Unfortunately some reading software also accepts “src” and also the well-known “PUB 3 Best Practices by Matt Garrish and Markus Gylling” wrongly use “src“ in their example. So many people might also try using “src” and are assured by calibres validation and then wonder why the resources are not found by some devices.