newsupernova/vendor/magento/module-braintree/etc/events.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="payment_method_assign_data_braintree">
        <observer name="braintree_gateway_data_assign" instance="Magento\Braintree\Observer\DataAssignObserver" />
    </event>
    <event name="payment_method_assign_data_braintree_paypal">
        <observer name="braintree_paypal_gateway_data_assign" instance="Magento\Braintree\Observer\DataAssignObserver" />
    </event>
</config>