Right click on the page -> Select Inspect -> Select Network tab

Click on the credit card icon to open Inline Guest.
Search for counter.cgi in the Network tab

Click on the request, copy the full Request Url in the right panel.
This is an example how the url looks like
https://b.stats.paypal.com/v2/counter.cgi?p=EC-7WG36255K9873394U&s=INLINE_GUEST
Fill out all the information and click Pay Now.
Search for graphql in the Network tab.
Click on the red request, in the Response Header section, look for Paypal-Debug-Id
This is an example how it looks like
Paypal-Debug-Id: cc44b915bc1d4