Maven: Overview for the values of Maven properties

Question

I would like to find out the values of all Maven properties as they apply to some Maven project.
mvn help:system lists OS environment variables and

Answer 1

Not sure if helps, but I found this when trying to do the same thing:

mvn com.github.ekryd.echo-maven-plugin:echo-maven-plugin:echo -Decho.message='${project.build.testOutputDirectory}'

From here