+ /**
+ * Page include parse event.
+ * Runs when a page include tag is being parsed, typically when page content is being processed for viewing.
+ * Provides the "include tag" reference string, the default BookStack replacement content for the tag,
+ * the current page being processed, and the page that's being referenced by the include tag.
+ * The referenced page may be null where the page does not exist or where permissions prevent visibility.
+ * If the listener returns a non-null value, that will be used as the replacement HTML content instead.
+ *
+ * @param string $tagReference
+ * @param string $replacementHTML
+ * @param Page $currentPage
+ * @param ?Page $referencedPage
+ */
+ const PAGE_INCLUDE_PARSE = 'page_include_parse';
+