It's been there for around 4 years. It automatically generates a one-time card for the payment, too, so you never hand the merchant your card.

https://www.html5rocks.com/en/tutorials/forms/requestautocom...

I think this API ended up being deprecated from lack of use (not surprising as no one used it and is amazed it existed), but it may have paved the way for https://developer.mozilla.org/en-US/docs/Web/API/Payment_Req....

Genuinely surprised that this didn't catch on, it was amazing.