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This internal representation leaks later in Maven public API: http://maven.apache.org/ref/3.0.4/maven-core/apidocs/org/apache/maven/project/MavenProject.html#getGoalConfiguration(java.lang.String, java.lang.String, java.lang.String, java.lang.String) MavenProject.getGoalConfiguration for example.
Then it has to let Xpp3Dom leak for plugins to be able to use this API: http://maven.apache.org/ref/3.0.4/maven-core/xref/org/apache/maven/classrealm/DefaultClassRealmManager.html#196
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