public string GetOriginEntityTypeName()

QueuedTask.Run(() =>
{
  //Create a connection properties
  var kg_props =
      new KnowledgeGraphConnectionProperties(new Uri(url));
  using (var kg = new KnowledgeGraph(kg_props))
  {
    //Get the KnowledgeGraph Data Model
    using (var kg_dm = kg.GetDataModel())
    {
      var dict_types = kg_dm.GetRelationshipTypes();

      foreach (var kvp in dict_types)
      {
        var rel_type = kvp.Value;
        var role = rel_type.GetRole();
        //note "name" will be the same name as the corresponding
        //feature class or table in the KG's relational gdb model
        var name = rel_type.GetName();
        //etc.
        //Get relationship end points
        var end_points = rel_type.GetEndPoints();
        foreach (var end_point in end_points)
        {
          System.Diagnostics.Debug.WriteLine(
            $"Origin: '{end_point.GetOriginEntityTypeName()}', " +
            $"Destination: '{end_point.GetDestinationEntityTypeName()}'");
        }
      }

    }
  }
});