payment_handler.js.LICENSE.txt in Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder trunk, at assets/js/payment_handler.js.LICENSE.txt
/*! @license DOMPurify 3.4.13 | (c) Cure53 and other contributors | Released under the Apache license 2.0 and Mozilla Public License 2.0 | github.com/cure53/DOMPurify/blob/3.4.13/LICENSE */