Quarto / MD
Markdown
"Markdown is a lightweight markup language for creating formatted text using a plain-text editor."
It's what's used for the HackMD presentations.
It's what's used for the Readme.md documentation files.
Why Quarto?
Quarto is an open source publishing system for technical and scientific documents. It implements Markdown, allowing for integration with multiple languages, (e.g. R and Python).