Universal attribute group

The universal attribute group defines a set of common attributes available on most DITA elements. The universal attribute group includes all attributes from the metadata, ID, localization, and debug attribute groups, plus the @class attribute.
Note: Earlier versions of the DITA specification grouped some attributes under names taken directly from parameter entities in the standard DTD implementation of DITA. These groups used names such as "univ-atts", which had no meaning outside the context of a DTD module. In DITA 1.3, these groups are restructured and renamed in the specification document for greater clarity, and no longer have a connection to the DTD. For example, this grouping of "Universal attributes" was previously referred to as "univ-atts"; the updated group includes several universal attributes that are not part of the univ-atts group in the DTD.
@class (Not for use by authors)
This attribute is not for use by authors. If an editor displays @class attribute values, do not edit them. The @class attribute supports specialization. Its predefined values allow DITA tools to work correctly with ranges of related content. In a generalized DITA document the @class attribute value in the generalized instance might differ from the default value for the @class attribute for the element as given in the DTD or schema. See @class attribute rules and syntax for more information. This attribute is specified on every element except for the <dita> container element. It is always specified with a default value, which varies for each element.