The source for the project website (http://flink.apache.org/) is located at https://github.com/apache/flink-web.
The website is regenerated nightly using buildbot.
The status of the buildbot builds can be seen at https://ci.apache.org/builders.
A list of buildbots is available at https://ci.apache.org/projects/flink/.
The builds use a shared build script located at https://svn.apache.org/repos/infra/infrastructure/buildbot/aegis/buildmaster/master1/projects/flink.conf that is accessible via SVN.