http://hl7.org/fhir/StructureDefinition/rendering-xhtml|4.0.1

This is an equivalent of the string on which the extension is sent, but includes additional XHTML markup, such as bold, italics, styles, tables, etc. Existing [restrictions on XHTML content](narrative.html#security) apply. Note that using [markdown](extension-rendering-markdown.html) allows for greater flexibility of display.