<specDesc> (descrizione di elemento o classe) indica il punto del documento nel quale deve essere inserita la descrizione di un dato elemento o di una data classe
The attribute names listed may include both attributes
inherited from a class and those defined explicitly for the associated
element. If the atts attribute is not supplied, then descriptions for all
non-inherited attributes are listed, along with references
to any classes. If an empty string is supplied as the value
for the atts attribute, then no
description should be displayed.
The description is usually displayed as a label and an item, with
any list of values defined for the attribute as an
embedded glossary list, No selection among the values is
possible. The list of attributes may include some which are inherited
by virtue of an element's class membership; descriptions for such
attributes may also be retrieved using another <specDesc>,
this time pointing at the relevant class.