mvn --help
Lists the profiles which are currently active for the build:
mvn help:active-profiles
Displays the effective POM for the current build, with the active profiles factored in:
help:effective-pom
Prints out the calculated settings for the project, given any profile enhancement and the inheritance of the global settings into the user-level settings:
help:effective-settings
To get help on a plugin:
mvn help:describe -Dplugin=xxx -Dfull
mvn help:describe -DgroupId=xxx -DartifactId=xxx -Dfull=true