Speculation-Rules header
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The HTTP Speculation-Rules response header provides one or more URLs pointing to text resources containing speculation rule JSON definitions. When the response is an HTML document, these rules will be added to the document's speculation rule set. See the Speculation Rules API for more information.
The resource file containing the speculation rules JSON can have any valid name and extension, but it must be served with an application/speculationrules+json MIME type.