How to Differ Heavy File during Loading?

Hi Guys! Following my previous post, we are improving the website based on your advices.

Anyone know how to differ these heavy files?

https://src.mastercard.com/srci/integration/merchant.js?locale=en_us&checkoutid=8f4c10f1499649f0b147e62aa221b07c 251KB

https://assets.secure.checkout.visa.com/checkout-widget/resources/src-system/js/srcSysExternalSdk.f688447e.js 193KB

https://assets.secure.checkout.visa.com/checkout-widget/resources/vba/js/vba-2.5.0.min.js 147KB

I have no idea why they are here and if they are even useful or not.

Thanks!