diff --git a/core/lib/Drupal/Core/Extension/ExtensionList.php b/core/lib/Drupal/Core/Extension/ExtensionList.php
index ebc2425..2bc63e8 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionList.php
@@ -11,6 +11,8 @@
 
 /**
  * Provides available extensions.
+ *
+ * The extension list is per extension type, like module theme and profile.
  */
 abstract class ExtensionList {
 
diff --git a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
index 516a550..088f3e4 100644
--- a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\State\StateInterface;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
@@ -57,8 +56,6 @@ class ModuleExtensionList extends ExtensionList {
    *   The info parser.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler.
-   * @param \Drupal\Core\State\StateInterface $state
-   *   The state service.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
    * @param \Drupal\Core\Extension\ExtensionList $profile_list
diff --git a/core/lib/Drupal/Core/Extension/ProfileExtensionList.php b/core/lib/Drupal/Core/Extension/ProfileExtensionList.php
index 8bae168..d7b0816 100644
--- a/core/lib/Drupal/Core/Extension/ProfileExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ProfileExtensionList.php
@@ -1,7 +1,15 @@
 <?php
 
+/**
+ * @file
+ * Contains \Drupal\Core\Extension\ProfileExtensionList.
+ */
+
 namespace Drupal\Core\Extension;
 
+/**
+ * Provides a list of installation profiles.
+ */
 class ProfileExtensionList extends ExtensionList {
 
   /**
diff --git a/core/modules/filter/tests/src/Kernel/FilterAPITest.php b/core/modules/filter/tests/src/Kernel/FilterAPITest.php
index 2514c76..93eae71 100644
--- a/core/modules/filter/tests/src/Kernel/FilterAPITest.php
+++ b/core/modules/filter/tests/src/Kernel/FilterAPITest.php
@@ -490,7 +490,7 @@ public function testDependencyRemoval() {
 
     drupal_static_reset('filter_formats');
     \Drupal::entityManager()->getStorage('filter_format')->resetCache();
-    $module_data =\Drupal::service('module_listing')->reset()->listExtensions();
+    $module_data = \Drupal::service('module_listing')->reset()->listExtensions();
     $this->assertFalse(isset($module_data['filter_test']->info['required']), 'The filter_test module is required.');
 
     // Verify that a dependency exists on the module that provides the filter
diff --git a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
index e644aa1..f958bf0 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
@@ -6,6 +6,7 @@
  */
 
 namespace Drupal\Tests\Core\Extension;
+
 use Drupal\Component\Serialization\Yaml;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\Extension;
@@ -15,7 +16,6 @@
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Tests\UnitTestCase;
 use org\bovigo\vfs\vfsStream;
-use org\bovigo\vfs\vfsStreamWrapper;
 use Prophecy\Argument;
 
 /**