public function showRedirectedFromHeader() {
		$context = $this->getContext();
		$redirectSources = $context->getConfig()->get( MainConfigNames::RedirectSources );
		$outputPage = $context->getOutput();
		$request = $context->getRequest();
		$rdfrom = $request->getVal( 'rdfrom' );
		// Construct a URL for the current page view, but with the target title
		$query = $request->getQueryValues();
		unset( $query['rdfrom'] );
		unset( $query['title'] );
		if ( $this->getTitle()->isRedirect() ) {
			// Prevent double redirects
			$query['redirect'] = 'no';
		}
		$redirectTargetUrl = $this->getTitle()->getLinkURL( $query );
		if ( $this->mRedirectedFrom ) {
			// This is an internally redirected page view.
			// We'll need a backlink to the source page for navigation.
			if ( $this->getHookRunner()->onArticleViewRedirect( $this ) ) {
				$redir = $this->linkRenderer->makeKnownLink(
					$this->mRedirectedFrom,
					null,
					[],
					[ 'redirect' => 'no' ]
				);
				$outputPage->addSubtitle( "<span class=\"mw-redirectedfrom\">" .
					$context->msg( 'redirectedfrom' )->rawParams( $redir )->parse()
				. "</span>" );
				// Add the script to update the displayed URL and
				// set the fragment if one was specified in the redirect
				$outputPage->addJsConfigVars( [
					'wgInternalRedirectTargetUrl' => $redirectTargetUrl,
				] );
				$outputPage->addModules( 'mediawiki.action.view.redirect' );
				// Add a <link rel="canonical"> tag
				$outputPage->setCanonicalUrl( $this->getTitle()->getCanonicalURL() );
				// Tell the output object that the user arrived at this article through a redirect
				$outputPage->setRedirectedFrom( $this->mRedirectedFrom );
				return true;
			}
		} elseif ( $rdfrom ) {
			// This is an externally redirected view, from some other wiki.
			// If it was reported from a trusted site, supply a backlink.
			if ( $redirectSources && preg_match( $redirectSources, $rdfrom ) ) {
				$redir = $this->linkRenderer->makeExternalLink( $rdfrom, $rdfrom, $this->getTitle() );
				$outputPage->addSubtitle( "<span class=\"mw-redirectedfrom\">" .
					$context->msg( 'redirectedfrom' )->rawParams( $redir )->parse()
				. "</span>" );
				// Add the script to update the displayed URL
				$outputPage->addJsConfigVars( [
					'wgInternalRedirectTargetUrl' => $redirectTargetUrl,
				] );
				$outputPage->addModules( 'mediawiki.action.view.redirect' );
				return true;
			}
		}
		return false;
	}