Apache License, Version 2.0, January 2004
The first and simplest usage is to configure the Maven Licenses Verifier Plugin
<plugin>
  <groupId>com.soebes.maven.plugins</groupId>
  <artifactId>doxygen-maven-plugin</artifactId>
  <version>1.1.0</version>
  <executions>
    <execution>
      <phase>test</phase>
      <goals>
        <goal>check</goal>
      </goals>
    </execution>
  </executions>
</plugin>
If you like you can configure an appropriate plugin group in your settings.xml file to make life a little bit easier.
<settings>
  ...
  <pluginGroups>
    <pluginGroup>com.soebes.maven.plugins</pluginGroup>
  </pluginGroups>
  ...
</settings>