It does not block Mastercard site on Crypto.

And for me, since my text size is a little larger than normal I could not see any method for removing the popup, which prevented me to using the web site. The two buttons for dealing with the popup, provided within the popup by Mastercard, were not seen by me and so I was not able to use the web site until I guessed that there might be some hidden buttons; which I then revealed by scaling down my font size. Such is the stupid life of Windoze users. I was using Firefox on Windows 10. When I browsed to the same web site using Firefox on the Mac, my system effectively blocked the popup without me even knowing it had.