This example shows how to configure an Angular CLI project for continuous integration in a headless Docker environment. It demonstrates replacing the default Chrome browser with Firefox, launched through Xvfb, a virtual frame buffer that provides an in-memory X11 display server. The code updates karma.conf.js to use the karma-firefox-launcher plugin and runs the test suite via xvfb-run, avoiding PhantomJS due to its incomplete ES6 and ES5 support.