Doxygen - Generate documentation from source code
GitBook - Modern Publishing, Simply taking your books from ideas to finished, polished books.
Wikitten - Wikitten is a small, fast, PHP wiki.
Docsify.js - A magical documentation site generator.
openKB - openKB is a Markdown Knowledge base application (FAQ) built with Nodejs and ExpressJS.
MkDocs - Project documentation with Markdown.