src/it/projects/container-descriptors/custom-handler-withMixedEntries/handler-def/src/main/resources/META-INF/plexus/components.xml

<component-set>
  <components>
    <component>
      <role>org.apache.maven.plugin.assembly.filter.ContainerDescriptorHandler</role>
      <role-hint>file.txt</role-hint>
      <implementation>org.apache.maven.plugin.assembly.filter.SimpleAggregatingDescriptorHandler</implementation>
      <configuration>
        <filePattern>.*file.txt</filePattern>
        <outputPath>file.txt</outputPath>
        <commentChars>#</commentChars>
      </configuration>
    </component>
  </components>
</component-set>