The sectiondiv element nests itself, so it can be specialized to
create structured information within sections. Another common use case for the
sectiondiv element is to group a sequence of related elements for
reuse, so that another topic can reference the entire set
with a single conref attribute.
Because the
sectiondiv element can only be used within section
elements, use the div element to group content that might occur in both
topic bodies and sections.