What does this Zig snippet output?

1const std = @import("std");
2const Packed3 = packed struct {
3    x: u4 = 15,
4    y: u4 = 0,
5};
6pub fn main() void {
7    const p = Packed3{};
8    const byte: u8 = @bitCast(p);
9    std.debug.print("{d}\n", .{byte});
10}