What is jetty-web.xml?
The jetty-web.xml file is a jetty configuration file that can be bundled with a specific web application. When jetty deploys a webapplication, it looks for a file called WEB-INF/jetty-web.xml or WEB-INF/web-jetty.xml within the web application (or WAR) and applies the configuration found there after all other configuration has been applied to the web application.
...
There is an example of this file in the distribution at $JETTY_HOME/webapps/test/WEB-INF/jetty-web.xml.