Enables web-based payment handlers to receive "paymentrequest" events with non-URL, but standardized payment method identifiers, such as "basic-card" or "tokenized-card".
Because standardized payment method identifiers do not have an allow or block list and can be installed silently, it could be surprising to the user to see a little known payment handler popup when they intend to make a payment via a credit card stored in the browser, for example.