In the last step of the checkout process, when the purchase is confirmed, woocommerce displays the checkout/thankyou.php template This template (parent template), using: do_action( 'woocommerce_thankyou', $order->get_id() ) embeds the template (child template) order/order-details.php The order/order-details.php template rendered in the browser appears wrapped by two nested <strong> tags: <strong> <strong></strong> </strong> In fact, if we remove the do_action( 'woocommerce_thankyou', $order->get_id() ) action, what we see on the front end is exactly that, the nested and empty <strong> tags. But neither the parent template nor the child template contain those <strong> tags. Where do they come from? How can I remove them? These are the templates involved (parent and child) https://github.com/woocommerce/woocommerce/blob/trunk/plugins/woocommerce/templates/checkout/thankyou.php https://github.com/woocommerce/woocommerce/blob/trunk/plugins/woocommerce/templates/order/order-details.php Please, if you are voting to close this question, at least explain to me why.