Adds an 'opt-out' flow to Secure Payment Confirmation. When the (optional) input flag is set, the SPC UXes will render an 'opt-out' link of some sort that the user can interact with to indicate to the relying party that they wish to be opted out. See https://github.com/w3c/secure-payment-confirmation/issues/172
In certain regions and situations, developers interacting with Secure Payment Confirmation may need to offer an opt-out experience - in which the user can indicate that they want their information removed from the developers server. Traditionally access to the opt-out experience is embedded directly into the Relying Party's website. However in the case of SPC the Relying Party may not be part of the web content flow, as the authentication may be initiated from a third-party website (e.g., a merchant site). In order to support these needs for an opt-out flow, we are experimenting with direct support for opt-out in the SPC browser UX. (Note that Chrome-stored information is NOT in scope here).
Docs: https://github.com/w3c/secure-payment-confirmation/issues/172
Samples: https://rsolomakhin.github.io/pr/spc-opt-out
Explainers: https://github.com/w3c/secure-payment-confirmation/issues/172