@spalger/kibana/src/ui/public/vislib/partials/legend_header.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

<div class="legend-toggle">
  <strong>
    <%= (isOpen) ?
      '<span class="legend-open">Legend <i class="fa fa-arrow-circle-right"></i></span>' :
      '<span class="legend-closed"><i class="fa fa-arrow-circle-left"></i></span>'
    %>
  </strong>
</div>