diff --git a/core/lib/Drupal/Core/Ajax/DialogController.php b/core/lib/Drupal/Core/Ajax/DialogController.php
index 41cdd02..eff0d1f 100644
--- a/core/lib/Drupal/Core/Ajax/DialogController.php
+++ b/core/lib/Drupal/Core/Ajax/DialogController.php
@@ -17,9 +17,9 @@
 class DialogController extends ContainerAware {
 
   /**
-   * Utility to get forward request to a subrequest.
+   * Forwards request to a subrequest.
    *
-   * @param Request $request
+   * @param \Symfony\Component\HttpFoundation\RequestRequest $request
    *   The request object.
    * @param callable $content
    *   The body content callable that contains the body region of this page.
@@ -27,7 +27,7 @@ class DialogController extends ContainerAware {
    * @return \Symfony\Component\HttpFoundation\Response
    *   A response object.
    */
-  protected function forward($request, $content) {
+  protected function forward(Request $request, $content) {
     // @todo When we have a Generator, we can replace the forward() call with
     // a render() call, which would handle ESI and hInclude as well.  That will
     // require an _internal route.  For examples, see:
@@ -46,9 +46,9 @@ protected function forward($request, $content) {
   }
 
   /**
-   * Wrapper to display content in a modal dialog.
+   * Displays content in a modal dialog.
    *
-   * @param Request $request
+   * @param \Symfony\Component\HttpFoundation\RequestRequest $request
    *   The request object.
    * @param callable $_content
    *   The body content callable that contains the body region of this page.
@@ -61,9 +61,9 @@ public function modal(Request $request, $_content) {
   }
 
   /**
-   * Wrapper to display content in a dialog.
+   * Displays content in a dialog.
    *
-   * @param Request $request
+   * @param \Symfony\Component\HttpFoundation\RequestRequest $request
    *   The request object.
    * @param callable $_content
    *   The body content callable that contains the body region of this page.
@@ -76,34 +76,16 @@ public function modal(Request $request, $_content) {
   public function dialog(Request $request, $_content, $modal = FALSE) {
     $subrequest = $this->forward($request, $_content);
     if ($subrequest->isOk()) {
-      $output = $subrequest->getContent();
-      // A page callback could return a render array or a string.
-      if (is_array($output)) {
-        // Subrequest has set dialog title in the output.
-        if (isset($output['title'])) {
-          $title = $output['title']['#value'];
-          unset($output['title']);
-        }
-        else {
-          // Legacy fallback.
-          // @todo remove when http://drupal.org/node/1830588 lands.
-          $title = drupal_get_title();
-        }
-        $content = drupal_render($output);
-      }
-      else {
-        // Legacy fallback.
-        // @todo remove when http://drupal.org/node/1830588 lands and all routes
-        // converted to return render arrays.
-        $title = drupal_get_title();
-        $content = $output;
-      }
+      $content = $subrequest->getContent();
+      // @todo Remove use of drupal_get_title() when
+      //  http://drupal.org/node/1871596 is in.
+      $title = drupal_get_title();
       $response = new AjaxResponse();
       // Fetch any modal options passed in from data-dialog-options.
       if (!($options = $request->request->get('dialogOptions'))) {
         $options = array();
       }
-      // Set modal flag and re-use the modal id.
+      // Set modal flag and re-use the modal ID.
       if ($modal) {
         $options['modal'] = TRUE;
         $target = '#drupal-modal';
diff --git a/core/lib/Drupal/Core/Routing/Enhancer/ModalEnhancer.php b/core/lib/Drupal/Core/Routing/Enhancer/ModalEnhancer.php
index c492e8c..652206b 100644
--- a/core/lib/Drupal/Core/Routing/Enhancer/ModalEnhancer.php
+++ b/core/lib/Drupal/Core/Routing/Enhancer/ModalEnhancer.php
@@ -7,9 +7,6 @@
 
 namespace Drupal\Core\Routing\Enhancer;
 
-use Symfony\Component\HttpFoundation\Request;
-use Drupal\Core\ContentNegotiation;
-
 /**
  * Enhances a route to use the DialogController for matching requests.
  */
diff --git a/core/modules/config/config.admin.inc b/core/modules/config/config.admin.inc
index 4e12ea4..57704de 100644
--- a/core/modules/config/config.admin.inc
+++ b/core/modules/config/config.admin.inc
@@ -79,7 +79,7 @@ function config_admin_sync_form(array &$form, array &$form_state, StorageInterfa
           'class' => array('use-ajax'),
           'data-accepts' => 'application/vnd.drupal-modal',
           'data-dialog-options' => json_encode(array(
-            'width' => 500
+            'width' => 700
           )),
         ),
       );
@@ -125,7 +125,7 @@ function config_admin_import_form_submit($form, &$form_state) {
   if (!lock()->lockMayBeAvailable(CONFIG_IMPORT_LOCK)) {
     drupal_set_message(t('Another request may be synchronizing configuration already.'));
   }
-  elseif (config_import()) {
+  else if (config_import()) {
     // Once a sync completes, we empty the staging directory. This prevents
     // changes from being accidentally overwritten by stray files getting
     // imported later.
diff --git a/core/modules/config/lib/Drupal/config/Controller/ConfigController.php b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
index 471d656..905c2bc 100644
--- a/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
+++ b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
@@ -30,14 +30,14 @@ class ConfigController implements ControllerInterface {
   protected $sourceStorage;
 
   /**
-   * Inject the target and source config storage services.
+   * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
     return new static($container->get('config.storage'), $container->get('config.storage.staging'));
   }
 
   /**
-   * Constructor.
+   * Constructs a ConfigController object.
    *
    * @param \Drupal\Core\Config\StorageInterface $target_storage
    *   The target storage.
@@ -89,13 +89,9 @@ public function diff($config_file) {
       '#href' => 'admin/config/development/sync',
     );
 
-    $title = t('View changes of @config_file', array('@config_file' => $config_file));
-    $output['title'] = array(
-      '#theme' => 'html_tag',
-      '#tag' => 'h3',
-      '#value' => $title,
-      '#weight' => -10,
-    );
+    // @todo Remove use of drupal_set_title() when
+    //   http://drupal.org/node/1871596 is in.
+    drupal_set_title('View changes of @config_file', array('@config_file' => $config_file));
 
     return $output;
   }
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index de16d51..144e5f5 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -1196,7 +1196,7 @@ protected function drupalGet($path, array $options = array(), array $headers = a
   }
 
   /**
-   * Retrieve a Drupal path or an absolute path and JSON decode the result.
+   * Retrieves a Drupal path or an absolute path and JSON decode the result.
    *
    * @param string $path
    *   Path to request AJAX from.
diff --git a/core/modules/system/tests/modules/ajax_test/ajax_test.module b/core/modules/system/tests/modules/ajax_test/ajax_test.module
index 2522c15..e7a252c 100644
--- a/core/modules/system/tests/modules/ajax_test/ajax_test.module
+++ b/core/modules/system/tests/modules/ajax_test/ajax_test.module
@@ -237,7 +237,7 @@ function _ajax_test_dialog($is_modal = FALSE) {
 }
 
 /**
- * Utlity function: Returns the contents for dialog tests.
+ * Returns example content for dialog tests.
  */
 function ajax_test_dialog_contents() {
   // This is a regular render array; the keys do not have special meaning.
diff --git a/core/modules/system/tests/modules/ajax_test/lib/Drupal/ajax_test/AjaxTestController.php b/core/modules/system/tests/modules/ajax_test/lib/Drupal/ajax_test/AjaxTestController.php
index c8ba8c4..53044c5 100644
--- a/core/modules/system/tests/modules/ajax_test/lib/Drupal/ajax_test/AjaxTestController.php
+++ b/core/modules/system/tests/modules/ajax_test/lib/Drupal/ajax_test/AjaxTestController.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\ajax_test;
 
+/**
+ * Provides content for dialog tests.
+ */
 class AjaxTestController {
 
   /**