In content metadata (RDFa metadata)¶

RDF metadata can be attached to elements in the 'content.xml'and 'styles.xml' file. Elements supporting this type of metadata have the following attributes :
xhtml:about
xhtml:property
xhtml:content
When metadata is added using these attributes, it is referrenced to as in content metadata. If 'content.xml' and 'styles.xml' files contain in content metadata, they shall be listed in the package's 'manifest.rdf' file.