Source for rspec.info.
Requires a recent version of Ruby (> 2.1.x, tested on 2.5.3), bundler and imagemagick (to generate favicons).
brew install imagemagick(or your package manager of choice).
Docker Setup + Development
If you don't have a local Ruby environment suitable to making changes to rspec.info, or prefer containerised development; you can find a 3rd party Docker image setup for this environment here: https://hub.docker.com/r/2performantirina/middleman-and-imagemagick/