Embedded RDF HTML Profile
A GRDDL-capable client tool, when visiting a page which contains the profile reference http://purl.org/NET/erdf/profile
will first visit this profile document and apply the
transformation declared here. The results of that transformation will
contain a statement identifying the transformation that should be
applied to
convert the originating document into RDF/XML. The GRDDL client has
everything it
needs to get RDF/XML from the original XHTML document, while the author
of
the originating document need not concern themselves with the details of
the
profile, merely including the reference to its URI is enough.
This following link provides the statement : extract-rdf.xsl, profile