What does this Zig snippet output?

1const std = @import("std");
2pub fn main() void {
3    const T = struct { val: u32 };
4    const arr = [_]T{ .{ .val = 10 }, .{ .val = 20 }, .{ .val = 30 } };
5    std.debug.print("{d}\n", .{arr[arr.len - 1].val});
6}