The ability for apps like PayPal to handle payments in the browser requires the Payment Handler API [1]. We aren't announcing support for Payment Handler here,

The ability for apps like PayPal to handle payments in the browser requires the Payment Handler API [1]. We aren't announcing support for Payment Handler here, just Payment Request. It's not like we're actively restricting or blocking these apps, we just haven't written the code to do this. [1] https://w3c.github.io/payment-handler/ https://w3c.github.io/payment-handler/