"Range Additional Members"

var characterArray = new[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G' };

var range = ^5..7;

Console.WriteLine(range.Start); // ^5
Console.WriteLine(range.End); // 7
Console.WriteLine(range.GetOffsetAndLength(characterArray.Length).Offset); // 2
Console.WriteLine(range.GetOffsetAndLength(characterArray.Length).Length); // 5