The page or section element to generate a link ID for.
This template outputs the fully qualified link ID for a page or section. For page elements, the link ID is identical to the ID. For section elements, however, the link ID is the containing page ID and the section ID, joined with the # character.
The link ID is used in Mallard cache files to ensure all id attributes are unique. All of the templates in this stylesheet that use a link ID use this template or mal.link.xref.linkid.