kibana-123/src/core_plugins/kibana/public/dashboard/partials/options.html

Kibana is an open source (Apache Licensed), browser based analytics and search dashboard for Elasticsearch. Kibana is a snap to setup and start using. Kibana strives to be easy to get started with, while also being flexible and powerful, just like Elastic

<form role="form">
  <div class="kuiLocalDropdownTitle">Options</div>
  <div class="input-group">
    <label>
      <input type="checkbox" ng-model="opts.ui.darkTheme" ng-checked="opts.ui.darkTheme">
      Use dark theme
    </label>
  </div>
</form>