Doxygen is a development software and application used to generate documentation from source code. It can generate documentation in a variety of formats including HTML, LaTeX, man pages, and XML. It can also be used to generate diagrams from code using DOT and other tools. Doxygen is used primarily in software development to generate documentation from source code, but it can also be used for other tasks such as creating project documentation, user manuals, and technical specifications. Doxygen is written in C++ and runs on Windows, Mac OS X, and Linux. It is open source and free to use.
Used to document REST APIs, where Doxygen is used to document libraries or source code, but not REST APIs.
Discontinued The project appears to no longer be under development. The latest version, 2.0.0 beta, released in July 2016, is still available for download from GitHub
The discontinued website is gone.
It seems to be limited to REST APIs.