The bundled Cinder source files includes documentation that you can view locally. You can find the online version here. If you are cloning the Cinder GitHub repo, the docs will need to be generated in your cloned local repo. This is a 2-step process.
Cinder uses Doxygen in part to generate documentation from the cinder_docs source files. You can generate the Doxygen output and tag file using Doxywizard. The Cinder latest release uses Doxywizard 1.8.10. You can download Doxywizard here.
This step builds out a directory of xml files and a cinder.tag file.
This next step generates the documentation from newly generated Doxygen output. It requires that you have python 2.7.x to run it.
python generateDocs.py
This process generates html files in the html directory. If the python file throws an error that results in incomplete docs, you can file a GitHub issue here. Your docs will be available at docs/index.html
For more detailed information about building docs and to learn how to contribute, follow this guide.