[BaryonBundle]

This reminds me of a comment[0] by a math grad student, Chao Xu, who extended markdown documents parsed by pandoc to ennumerate Proofs, Lemmas, etc., leading to blog posts that feel like part of a math text. One starts with a line beginning with, e.g., {proof}, and any content that follows and is indented (until non-indented text) is included with this section.

EDIT: also wanted to add that most markdown parsers that I've used (pandoc, python markdown) have support for footnotes and tables, though footnotes are compiled at the end of the document instead of at the end of individual 'sections' or 'subsections', which is a major pain for longer documents.

[0]: https://news.ycombinator.com/item?id=7913498