what does <!-- ngView : undefined --> mean

I get a dom like this:

<div class="row">
  <::before>
    <div class="col-lg-12">
      <!-- ngView: undefined -->
        <ng-view class="ng-scope">
          <h1 class="ng-scope">Hello world</h1>
        </ng-view>
    </div>
  <::after>
</div>

What does:

    <!-- ngView: undefined -->

mean?

Everything seems to work fine, but I don't like this comment as it seems that something is not working properly?

The template look like this:

<h1>Hello world</h1>

and it is configured like this :

var myApp = angular.module('myApp', [
'ngRoute',

.....

]);

myApp.config(['$routeProvider', function($routeProvider){
$routeProvider.when('/my_template', {templateUrl: '/web-angular/my_template.html'})
.when( .....  );
}]);