IList<DisplayUnitFormat> GetProjectUnitFormats( 
   UnitFormatType unitFormat
)

{
  // Note: Must be on the QueuedTask.Run()
  var unit_formats = Enum.GetValues(typeof(UnitFormatType))
                  .OfType<UnitFormatType>().ToList();
  System.Diagnostics.Debug.WriteLine("Project units\r\n");
  foreach (var unit_format in unit_formats)
  {
    var units = DisplayUnitFormats.Instance.GetProjectUnitFormats(unit_format);
    System.Diagnostics.Debug.WriteLine(unit_format.ToString());

    foreach (var display_unit_format in units)
    {
      var line = $"{display_unit_format.DisplayName}, {display_unit_format.UnitCode}";
      System.Diagnostics.Debug.WriteLine(line);
    }
    System.Diagnostics.Debug.WriteLine("");
  }
}

{
  //Must be on the QueuedTask.Run()

  //UnitFormatType.Angular, UnitFormatType.Area, UnitFormatType.Distance, 
  //UnitFormatType.Direction, UnitFormatType.Location, UnitFormatType.Page
  //UnitFormatType.Symbol2D, UnitFormatType.Symbol3D
  var units = DisplayUnitFormats.Instance.GetProjectUnitFormats(UnitFormatType.Distance);
  // Use units;
}

{
  //UnitFormatType.Angular, UnitFormatType.Area, UnitFormatType.Distance, 
  //UnitFormatType.Direction, UnitFormatType.Location
  var angle_units = DisplayUnitFormats.Instance.GetProjectUnitFormats(UnitFormatType.Angular);

  //Edit the display name of each unit - append the abbreviation
  foreach (var unit in angle_units)
  {
    unit.DisplayName = $"{unit.DisplayName} ({unit.Abbreviation})";
  }
  //apply the changes to the units and set the default to be the first entry
  DisplayUnitFormats.Instance.SetProjectUnitFormats(angle_units, angle_units.First());
  //The project must be saved to persist the changes...
}