This extends the speculation rules [1] syntax to allow developers to specify the referrer policy to use with speculative requests triggered by speculation rules. This also reintroduces the "sufficiently-strict referrer policy" requirement [2]. [1] https://chromestatus.com/feature/5740655424831488 [2] https://github.com/WICG/nav-speculation/blob/main/fetch.md#stripping-referrer-information
By default, the referring document's referrer policy is used for the speculative request. The use of a "referrer_policy" key in speculation rules allows the referrer policy to be set explicitly. For speculation actions that would be prevented by the "sufficiently-strict referrer policy" requirement [2] on a referring page with a lax policy, this allows the referring page to set a stricter policy specifically for the speculative request. We now reintroduce the enforcement of the sufficiently-strict referrer policy, as the referrer policy key introduces the necessary capability for sites to specify an acceptable policy.
Explainers: https://github.com/WICG/nav-speculation/blob/main/triggers.md#explicit-referrer-policy