There are no defaults.
Jetty is used only for running the app locally. Kind of a smoke test.
Several other apps that use Maven for build use this version of Jetty. It is a bit old but I kept it consistent.

For the real test execution (production) most of the JVM based apps are deployed in Resin, so this plugins are not used there at all.

As you can see few lines above this particular application uses tomcat-maven-plugin for the same purpose. Again the plugin is outdated. Latest version of it is 2.2. 
The problem is that I cannot run this app locally with both. So I will remove this extra plugin that I added.

I think the best would be to use Resin as in production, but I'm not sure whether they have Maven plugin.