Remove/un-enqueue the jQuery migrate file, which is often not required.

remote-jquery-migrate.php

<?php
/**
 * Removes the jquery-migrate file, often not-required.
 */
add_filter('wp_default_scripts', 'remove_jquery_migrate');
function remove_jquery_migrate(&$scripts)
{
    if (!is_admin()) {
        $scripts->remove('jquery');
        $scripts->add('jquery', false, array('jquery-core'), '');
    }
}