^ specifies the index from the end of a sequence. It simplifies the calculation required to get the correct index from the start of the array. Now, you can directly specify the index from the end, which is easier to understand and shorter.
e.g., Get the second last item of an array
PROGRAM
using System; namespace MyTestConsole { class Program { static void Main() { var array = new[] { 1, 2, 3, 4, 5, 23, 45, 56, 78, 89 }; // Before var x = array[array.Length - 2]; // 4 Console.WriteLine($"[BEFORE] Second last item is {x}"); // Now this is also allowed var y = array[^2]; // 4 Console.WriteLine($"[AFTER] Second last item is {y}"); Console.ReadKey(); } } }