Attributes rel and rev now have defined values:
- alternate, appendix, bookmark, cite
- chapter, contents, copyright, first
- glossary, help
- icon
- Refers to a resource that represents an icon.
- index, last, license
- meta
- Refers to a resource that provides metadata, for instance in RDF.
- next
- p3pv1
- Refers to a P3P Policy Reference File
- prev
- role
- Indicates the purpose of the resource.
- section, stylesheet, subsection, start, top
- up
- Refers to the resource above in a hierarchically
structured set