framework/RedKiteCms/EventSystem/Listener/PageCollection/PageRemovedListener.php
public function onPageRemoved(PageCollectionRemovedEvent $event)
    {
        $pageName = basename($event->getFilePath());
        $page = $this->pagesParser
            ->contributor($event->getUsername())
            ->parse()
            ->page($pageName);
        if (null === $page) {
            return;
        }

        foreach ($page["seo"] as $seo) {
            $permalink = $seo["permalink"];
            $this->permalinkManager->remove($permalink);
        }

        $this->permalinkManager->save();
    }
public function onPageRemoved(PageCollectionRemovedEvent $event)
    {
        $pageName = basename($event->getFilePath());
        $page = $this->pagesParser
            ->contributor($event->getUsername())
            ->parse()
            ->page($pageName);
        if (null === $page) {
            return;
        }

        foreach ($page["seo"] as $seo) {
            $permalink = $seo["permalink"];
            $this->permalinkManager->remove($permalink);
        }

        $this->permalinkManager->save();
    }
Removes the page from PermalinkManager object

@param \RedKiteCms\EventSystem\Event\PageCollection\PageCollectionRemovedEvent $event