Usage
To use the maven-enforcer-extension, you must register the extension and configuration.
Maven Extension
You have 2 ways to use Maven extensions within your builds:
- 
add maven-enforcer-extension-3.2.1.jarin${maven.home}/lib/ext(no extra dependencies required),
- 
(since Maven 3.3.1) configure your extension in .mvn/extensions.xml. 
There is actually a third way: add the extension to the pom.xml, but in that case it makes more sense to use the maven-enforcer-plugin instead.
Enforcer Extension
The .mvn/enforcer-extension.xml in the root of your Maven project is where you define your rules.
It's content is similar to an execution-block of the maven-enforcer-plugin
<extension>
  <executions>
    <execution>
      <id/> <!-- default: default-extension -->
      <phase/> <!-- default: validate -->
      <configuration> <!-- see Plugin Configuration -->
        <rules/>
      </configuration>
    </execution>
  </executions>
</extension>



