public function linkToAllSiteRSSFeed()
    {
        if (!Config::inst()->get(VersionFeed::class, 'allchanges_enabled')
            || !SiteConfig::current_site_config()->AllChangesEnabled
        ) {
            return;
        }
        
        // RSS feed to all-site changes.
        $title = Convert::raw2xml($this->linkToAllSitesRSSFeedTitle());
        $url = $this->owner->getSiteRSSLink();

        Requirements::insertHeadTags(
            '<link rel="alternate" type="application/rss+xml" title="' . $title .
            '" href="' . $url . '" />'
        );
    }