This is the documentation for PHOEBE 2 and is available in a compiled version on the PHOEBE documentation website.
The master branch is intentionally left empty except for the built versions of ipynb and py files (which are managed by travis so that they can be hosted by GitHub pages), as each minor release of PHOEBE has its own documentation in a corresponding branch in this repository. See, for example, the 2.0 branch for up-to-date documentation for PHOEBE 2.0.x.