+'UndeleteForm::showHistory': called in UndeleteForm::showHistory, after a
+PageArchive object has been created but before any further processing is done.
+&$archive: PageArchive object
+$title: Title object of the page that we're viewing
+
+'UndeleteForm::showRevision': called in UndeleteForm::showRevision, after a
+PageArchive object has been created but before any further processing is done.
+&$archive: PageArchive object
+$title: Title object of the page that we're viewing
+
+'UndeleteForm::undelete': called un UndeleteForm::undelete, after checking that
+the site is not in read-only mode, that the Title object is not null and after
+a PageArchive object has been constructed but before performing any further
+processing.
+&$archive: PageArchive object
+$title: Title object of the page that we're about to undelete
+