The core of Jetty has no external dependencies other than the servlet-api, but it does have several optional 3rd party jars.
The individual jetty jars may be used directly by constructing your own classpath, or the start.jar utility can be used to build a classpath. The aggregate jars may also used to reduce the number of jars required. During development, the maven build tool is ideal for accessing jetty jars and their dependencies.
The Jetty Dependencies reference explains the jars.