运行Maven site时无法生成plugin-info.html文件的问题求助

我开发了一个包含多个Goals/Mojos的自定义Maven插件，按照《Maven插件文档指南》要求，结合maven-plugin-plugin与maven-site-plugin生成包含Goals信息的plugin-info.html文件，但运行mvn clean site或mvn site:site后，仅生成target/site目录及其他文件，没有plugin-info.html，也未展示任何Goals/Mojos相关信息。

已完成的配置 #

1. reporting段配置maven-plugin-plugin #

<reporting>
    <plugins>
        ...
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-plugin-plugin</artifactId>
            <version>3.9.0</version>
        </plugin>
    </plugins>
</reporting>

2. build/plugins段配置 #

<build>
    ...
    <plugins>
        ...
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-site-plugin</artifactId>
            <version>3.12.1</version>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-plugin-plugin</artifactId>
            <version>3.9.0</version>
            <executions>
                <execution>
                   <id>generate-helpmojo</id>
                   <goals>
                       <goal>helpmojo</goal>
                   </goals>
               </execution>
            </executions>
        </plugin> 
    </plugins>
</build>

3. Mojo代码示例（配置确认正确） #

/**
 * Run the configured recipes and apply the changes locally.
 * <p>
 * This variant of rewrite:run will fork the maven life cycle and can be run as a "stand-alone" goal. It will
 * execute the maven build up to the process-test-classes phase.
 */
@Mojo(name = "run", requiresDependencyResolution = ResolutionScope.TEST, threadSafe = true,
        defaultPhase = LifecyclePhase.PROCESS_TEST_CLASSES)
@Execute(phase = LifecyclePhase.PROCESS_TEST_CLASSES)
public class RewriteRunMojo extends AbstractRewriteRunMojo {
}

4. 已验证的中间产物 #

运行mvn process-classes时，能正确生成包含Goals信息的target/classes/META-INF/maven/.../plugin-help.xml文件，示例片段：

...
<mojo>
  <goal>run</goal>
  <description>Run the configured recipes and apply the changes locally. 
This variant of rewrite:run will fork the maven life cycle and can be run as a stand-alone goal. It will execute the maven build up to the process-test-classes phase.
  </description>
  ...
</mojo>

疑问 #

plugin-help.xml已正确生成，但maven-site-plugin未据此生成plugin-info.html，请问是否遗漏了命令或配置？还需提供哪些相关信息？

内容的提问来源于stack exchange，提问作者Mike Solomon