Later in the file you are likely to find a tag
(«comments» in the slash namespace), and a tag («comments» not in a declared namespace).
I do have the authority to say that XML messages they transform from proprietary must have
a declared namespace meaning that they have to transform the message into some format that is distinctly different.
Not exact matches
For convenience, the following
namespace prefixes [XMLNS] are used in this specification without explicitly being
declared.
The EPUB 3 CSS Profile includes the @
namespace rule defined in [CSS
Namespaces] for declaring the default namespace for a style sheet and for binding prefixes to n
Namespaces] for
declaring the default
namespace for a style sheet and for binding prefixes to
namespacesnamespaces.
For future compatibility with alternative serializations of the Package Document, a prefix for the Dublin Core / elements / 1.1 /
namespace [DCTERMS] must not be
declared in the prefix attribute.