What is a Content-Location header?
An alternate location for the returned data, useful when content negotiation has selected a specific representation.
Content-Location points to the specific representation of a resource a website actually returned, which matters when content negotiation (via Accept, Accept-Language, and so on) means the same URL can serve different variants to different clients. It's a fairly niche header outside of APIs that lean heavily on content negotiation, but a useful piece of transparency when they do.
Common use case
An API that negotiates content by language returns Content-Location pointing at the specific /en-GB/ variant it selected, so a client can bookmark or cache that exact representation directly.
Example
Content-Location: /articles/482/en-gbHistory
Part of the original HTTP/1.1 specification, RFC 2068 (1997).
Did you know?
It's easy to confuse with the Location header used for redirects, but the two serve completely different purposes - this one describes what was returned, Location says where to go next.