The master branch of the handbook repo is published on the Code For Nashville website. The markdown is rendered into html using Showdown.js.
To test how changes to the handbook will look rendered on the site you can serve the files using static-server.py. Then in js/markdown.js you can point the url to fetch the markdown file to the python server at 0.0.0.0:8000 instead of the github cdn.
The site paths for the documents should match the directory structure of this repo as the files are fetched dynamically based on the path.