DocBook - DocBook is a schema (available in several languages including RELAX NG, SGML and XML DTDs, and W3C...
GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.
pandoc - Pandoc is a Haskell library for converting from one markup format to another, and a command-line...
MkDocs - Project documentation with Markdown.
Asciidoctor - In the spirit of free software, everyone is encouraged to help improve this project.
Docusaurus - Easy to maintain open source documentation websites