X-apple-i-md-m ((better)) Instant

As a developer or security researcher, you will encounter this header in three primary contexts:

Apple uses a suite of headers starting with x-apple-i-md- to establish a "Chain of Trust." The suffix -m in x-apple-i-md-m typically stands for or Metadata . x-apple-i-md-m

If you are running a server that acts as a proxy or gateway for iOS requests (e.g., a corporate MITM proxy, a caching server, or an API gateway), you might wonder how to treat this header. As a developer or security researcher, you will