treelite.io is no longer a valid site and re-directs users to a parked domain. Re-directing to the documentation is safer at this point.
The documentation of xgboost is generated with recommonmark and sphinx. You can build it locally by typing "make html" in this folder. Checkout https://recommonmark.readthedocs.org for guide on how to write markdown with extensions used in this doc, such as math formulas and table of content.