Extension descriptor, stored in <code>META-INF/maven/extension.xml</code> in an extension's jar artifact to
    precisely control parts of the extension and dependencies to expose in the API class loader.
    Maven uses Plexus Classworlds to build the class loader hierarchy, therefore some concepts used in this extensions
    stem from Plexus Classworlds originally.

          <type>String</type>
        </field>
        <field>
          <name>layout</name>
          <version>4.0.0+</version>
          <description>
            The type of layout this repository uses for locating and storing artifacts -
            can be {@code legacy} or {@code default}.
          </description>
          <type>String</type>
          <defaultValue>default</defaultValue>
        </field>

                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <!--
                A plugin which uses the JUnit framework in order to start
                our junit suite "AllTests" after the sources are compiled.
                -->
                <artifactId>maven-surefire-plugin</artifactId>

     | This will make it more intuitive to understand what the set of introduced profiles is attempting
     | to accomplish, particularly when you only have a list of profile id's for debug.
     |
     | This profile example uses the JDK version to trigger activation, and provides a JDK-specific repo.
    <profile>
      <id>jdk-1.4</id>

      <activation>
        <jdk>1.4</jdk>
      </activation>

      <repositories>

          <type>String</type>
        </field>
        <field>
          <name>layout</name>
          <version>1.0.0+</version>
          <description>
            The type of layout this repository uses for locating and
            storing artifacts - can be "legacy" or "default".
          </description>
          <type>String</type>
          <defaultValue>default</defaultValue>
        </field>
      </fields>