polygerrit-ui/app/elements/change/gr-change-metadata/test/plugin.html

<dom-module id="my-plugin">
  <script>
    Gerrit.install(plugin => {
      plugin.registerStyleModule('change-metadata', 'my-plugin-style');
    });
  </script>
</dom-module>

<dom-module id="my-plugin-style">
  <style>
    html {
      --change-metadata-assignee: {
        display: none;
      }
      --change-metadata-label-status: {
        display: none;
      }
      --change-metadata-strategy: {
        display: none;
      }
      --change-metadata-topic: {
        display: none;
      }
    }
  </style>
</dom-module>