In 2011, another Standards Track RFC described Metalink in HTTP header fields.

This status check web API should return 303 See Other to the caller when the task is complete, along with a URI from which to retrieve the result in the Location HTTP header field.

The X-Forwarded-For (XFF) HTTP header field is a de facto standard for identifying the originating IP address of a client connecting to a web server through an HTTP proxy or load balancer.

The Do Not Track (DNT) header is the proposed HTTP header field that requests that a web application disable either its tracking or cross-site user tracking (the ambiguity remains unresolved) of an individual user.

For increased convenience, the multiple download locations for a file (FTP/HTTP/P2P) and other metadata are made available in HTTP header fields and/or an XML file with the extension or .

Metalink in HTTP header fields makes use of existing standard HTTP header fields such as ETags, Link header fields (for mirrors and P2P), and Instance Digests (for hashes).