Code-Snippets-Functions/Execute a function on a child site/WooCommerce/add-product-names-in-new-order-email-notification-subject.txt

add_filter('woocommerce_email_subject_new_order', 'change_email_subject_new_order', 10, 2);
function change_email_subject_new_order( $formatted_subject, $order ) {
    $products = array(); // Initializing

    // Loop through order items
    foreach( $order->get_items() as $item ){
        // Add formatted product name and quantity to the array
        $products[] = sprintf( '%s × %d', $item->get_name(), $item->get_quantity() );
    }

    $count    = count($products); // Products count
    $products = implode(', ', $products); // Convert the array to a string

    return sprintf( 
        __('[%s] New Customer Order (# %s), %s, from %s %s', 'woocommerce'), 
        wp_specialchars_decode(get_option('blogname'), ENT_QUOTES), $order->get_order_number(), 
        sprintf( _n('Product (%s)', 'Products (%s)', $count, 'woocommerce'), $products, $products ),
        $order->get_billing_first_name(), $order->get_billing_last_name() 
    );
}