Transforms related to the front matter of a document or a section
(information found before the main text):
- DocTitle: Used to transform a lone top level section's title to
the document title, promote a remaining lone top-level section's
title to the document subtitle, and determine the document's title
metadata (document['title']) based on the document title and/or the
"title" setting.
- SectionSubTitle: Used to transform a lone subsection into a
subtitle.
- DocInfo: Used to transform a bibliographic field list into docinfo
elements.