Markedly Structured Text (MyST)
The relationship between MyST, reStructuredText, and Sphinx
Sphinx is a documentation generation framework written in Python. It heavily-utilizes reStructuredText syntax, which is another markup language for writing documents. In particular, Sphinx defines two extension points that are extremely useful: in-line roles and block-level directives.
MyST markdown provides a markdown equivalent of the reStructuredText syntax, meaning that you can do anything in MyST that you can do with reStructuredText.