'[taxonomy=product_tag]', 'Get product brands:' => '[taxonomy=brand]', ); public $display_name = 'Taxonomy ...'; public function getValue($post, $field) { if ('product' === $post->post_type) { return $this->termsObjectsToString(get_the_terms($post, $field['value'])); } if ('product_variation' === $post->post_type) { return $this->termsObjectsToString(get_the_terms($post->post_parent, $field['value'])); } } }