title: VScode webview extension api
body: <p>When I read the VScode API <a href="https://code.visualstudio.com/api/advanced-topics/remote-extensions" rel="nofollow noreferrer">Supporting Remote Development and GitHub Codespaces</a>, I saw</p>
  <pre><code>import { getExpressServerPort } from './server'
  </code></pre>
  <p>I want to make my webview extension to connect to my localhost website, but I can't import <code>getExpressServerPort</code>. Where is the './server'?</p>