Verifying iTunes Codes
Mac Option
You can verify iTunes on the Mac app store from a Mac. (This will not work for an iPhone anymore)
Open the App Store (not iTunes)
Go to redeem
Enter in the code.
If it's good it will say This code must be redeemed in the iTunes store
If it's used it will say it's already been redeemed.
As of 9/18/19 xml will verify the same as any other code. Will still redeem SD
If it's not an iTunes code it will say invalid.