Square API Release Notes (2017-10-30)
Release Summary: Square payment form
Starting 2017-10-18 Square’s payment form will accept MasterCard Masterpass payments. MasterPass is a free digital wallet designed to make online shopping easier by storing all of your payment and shipping information in one convenient location
Square payment form (SqPaymentForm)
SqPaymentForm now looks for HTML placeholders associated with Masterpass. If the HTML placeholders exist and Masterpass is enabled, a Masterpass button will display as part of the Square Payment form.
To learn more about how to integrate with Masterpass see Configuring Masterpass. or our example code on Github: