core-it-suite/src/test/resources/mng-7891-extension-configuration/build-extension/pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.1.0" root="true">
  <groupId>org.apache.maven.its.mng7891</groupId>
  <artifactId>build-extension</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <build>
    <extensions>
      <extension>
        <groupId>org.apache.maven.its.mng7891</groupId>
        <artifactId>extension</artifactId>
        <version>1.0-SNAPSHOT</version>
        <configuration>
          <messages>
            <sessionStart>The session has just started at ${maven.build.timestamp}</sessionStart>
            <projectsRead>All projects are read now! The build will start and the user has passed -DuserValue=${userValue} on the commandline</projectsRead>
          </messages>
        </configuration>
      </extension>
    </extensions>
  </build>
</project>