The CAS project source code can be found in GitHub at https://github.com/apereo/cas. It is not really required to check out the source code, build the CAS server, and then deploy it. WAR overlay is an approach wherein, rather than downloading the source and building, we get a pre-built CAS web application and then we can customize certain behavior as needed for achieving our use case. We will be using this approach to set up our CAS server. Also, we will use Maven-based WAR overlay, which can be found in GitHub at https://github.com/apereo/cas-overlay-template.