The Dublin Core module belongs to the RSS 1.0 standard; even though it is defined explicitly as a module, and, therefore, has its own namespace. In this way, defining again within RSS things that already have an RDF version and an RDF/XML vocabulary can be avoided.
The integration of the Dublin Core module also allows for future extensions of this module to be used. The specifications of the modules also refers to the Dublin Core standard itself for the definition of the Dublin Core elements.
The Dublin Core is a set of metadata developed by a team of librarians who work on the Web. In 1995, the group met for the first time in Dublin (not Dublin, Ireland, but Dublin,
Ohio, in the United States!); that’s where ...