x-apple-i-md-m: AQIDBAUGBwgJCgsMDQ4PEBESExQVFhcYGRobHB0eHyAhIiM=
The value associated with x-apple-i-md-m is typically a Base64-encoded string. While the exact implementation is proprietary and has evolved over time, the underlying structure generally follows Apple's standards. x-apple-i-md-m