+ /**
+ * For the purposes of this class, "metadata" elements are those that
+ * should neither trigger p-wrapping nor stop an outer p-wrapping,
+ * typically those that are themselves invisible in a browser's rendering.
+ * This isn't a complete list, it's just the tags that we're likely to
+ * encounter in practice.
+ * @var array
+ */
+ private static $metadataElements = [
+ 'style' => true,
+ 'script' => true,
+ 'link' => true,
+ 'meta' => true,
+ ];
+