This is the default type for all of the DC elements. It permits text content only with optional xml:lang attribute. Text is allowed because mixed="true", but sub-elements are disallowed because minOccurs="0" and maxOccurs="0" are on the xs:any tag. This complexType allows for restriction or extension permitting child elements.
In due course, we should install the relevant ISO 2- and 3-letter codes as the enumerated possible values . . .
Source
<xs:complexType name="SimpleLiteral"><xs:annotation><xs:documentation xml:lang="en">This is the default type for all of the DC elements. It permits text content only with optional xml:lang attribute. Text is allowed because mixed="true", but sub-elements are disallowed because minOccurs="0" and maxOccurs="0" are on the xs:any tag. This complexType allows for restriction or extension permitting child elements.</xs:documentation></xs:annotation><xs:complexContent mixed="true"><xs:restriction base="xs:anyType"><xs:sequence><xs:any processContents="lax" minOccurs="0" maxOccurs="0"/></xs:sequence><xs:attribute ref="xml:lang" use="optional"/></xs:restriction></xs:complexContent></xs:complexType>