anchor.diff:                +footnote('hn-phrasing-content-model')
                 +footnote('p-phrasing-content-model')
                 +footnote('pre-phrasing-content-model')
  +              +footnote('legend-phrasing-content-model')
  +              +footnote('summary-phrasing-content-model')
               | An element with a #[dfn#phrasing-content-model Phrasing Content Model] may contain only Phrasing Content children. 
               small All text-level elements have the Phrasing Content Model unless otherwise specified.
             li
  
positive.code:               +footnote('figure-sectioning-root')
                +footnote('blockquote-sectioning-root')
                +footnote('td-sectioning-root')
              | #[dfn Sectioning Roots] have their own outlines, but they are encapsulated,
              |  hidden from the Document Outline (#[abbr.c-Acro#document-outline(title="document outline") DO]).
            li
  
negative.code:         ul
            li #[code img] #[+tag('Nothing Content Model','img-nothing-content-model')]
        section
          h2 Form Content
          ul
            li #[code fieldset] #[+tag('Sectioning Root','fieldset-sectioning-root')]
            li #[code legend] #[+tag('Phrasing Content Model','legend-phrasing-content-model')]
            li #[code input] #[+tag('Nothing Content Model','input-nothing-content-model')]
            li #[code label] #[+tag('Phrasing Content Model','label-phrasing-content-model')] #[sup: +reference('label')]
        section
          h2 Interactive Content
          ul
            li #[code details] #[+tag('Sectioning Root','details-sectioning-root')]
            li #[code summary] #[+tag('Phrasing Content Model','summary-phrasing-content-model')] #[sup: +reference('summary')]
            li #[code dialog] #[+tag('Sectioning Root','dialog-sectioning-root')]
        footer
          ul.c-ListFootnotes
            li
  