This is the website for Reach UI.
The site is hosted on Firebase Hosting, which serves anything in the public directory. You probably don't want to update anything in the public directory directly though, because it will be wiped out the next time someone pushes to the website branch in the Reach UI repo.
You can run the site locally using firebase serve. You'll have to install firebase-tools globally first using npm i -g firebase-tools.
The website automatically deploys (using a job on Travis CI) when you push to the master branch. You can see a history of builds of this site on Travis CI.