Spectrum as a framework contains a command-line tool (spectrum-cli) to generate the react/redux template code and build the js/css bundles using webpack. It generates shell scripts to push those bundles into CDN. It has a hosted static server (spectrum-static) to serve the index.html and other static contents like fonts, icons and images. The below diagram shows the boot sequence.
Spectrum server is built using the core unity libraries. It is the layer below the Knuth (Api Gateway). It handles the web server session, login and logout.