The email team requested a credit card payments form variant with a lock icon next to the card number label, since this has apparently improved results for other orgs. I worked out some CSS to do it, but am not sure how to turn this snippet into a form variant
[data-id=encryptedCardNumber] { padding-left: 16px; background: url(https://payments.wikimedia.org/extensions/DonationInterface/gateway_forms/includes/padlock.gif) no-repeat left center; }