To build the documentation, follow the steps below.
Install Doxygen.
Install sphinx, breathe and the theme using the requirements.txt file in docs/:
pip install -r requirements.txt
From docs/:
doxygen && make html
If you run into issues rebuilding the docs, run make clean before building again.
Run a server in docs/build/html:
python -m http.server <port>
Point browser to http://localhost:<port>.