<div>
  <p>
  Extensions add new behavior or modify existing plugin behavior for different uses.
  Extensions help users more precisely tune plugin behavior to meet their needs.
  </p>
  <p>
  Extensions include:
    <ul>
      <li>
        <strong>Clone extensions</strong> modify the git operations that retrieve remote changes into the agent workspace.
        The extensions can adjust the amount of history retrieved, how long the retrieval is allowed to run, and other retrieval details.
      </li>
        <strong>Checkout extensions</strong> modify the git operations that place files in the workspace from the git repository on the agent.
        The extensions can adjust the maximum duration of the checkout operation, the use and behavior of git submodules, the location of the workspace on the disc, and more.
      <li>
        <strong>Changelog extensions</strong> adapt the source code difference calculations for different cases.
      </li>
        <strong>Tagging extensions</strong> allow the plugin to apply tags in the current workspace.
      <li>
        <strong>Build inititation extensions</strong> control the conditions that start a build.
        They can ignore notifications of a change or force a deeper evaluation of the commits when polling.
      </li>
      <li>
        <strong>Merge extensions</strong> can optionally merge changes from other branches into the current branch of the agent workspace.
        They control the source branch for the merge and the options applied to the merge.
      </li>
    </ul>
  </p>
</div>

Add intro help for extensions
Add intro help for extensions
