esri-leaflet Legend from Service

<!--
  1. Load legend json from the service
-->
<script>
  var myService = 'http://fake.com/arcgis/rest/services/Timor/IlliteracyRate/MapServer';
  $.ajax({
      url: myService + '/legend',
      data:{f: 'pjson'},
      dataType: 'jsonp'
  }).then(function(esriLegend){
      _.template(Template)({esriLegend: esriLegend});
  });
</script>

<!-- HTML for a _.template file that parses the json, and creates images for it.
<%  _.each(esriLegend, function(legend) {
      if (legend.label && legend.imageData) {
    %>
    <div>
       <img src="data:<%=  legend.contentType %>;base64,<%=  legend.imageData %>" class="color-block" />
        <%= legend.label %>
    </div>
    <% }
   }); %>
<% } %>

Do you have a working example of this? I'd like to try to implement it, but have never worked with whatever is going on at line 16. What kind of tag is that?