diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index 0294385..d86c338 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -641,7 +641,9 @@ function forum_form_node_form_alter(&$form, &$form_state, $form_id) {
 }
 
 /**
- * A #pre_render callback. Lists nodes based on the element's #query property.
+ * Render API callback: Lists nodes based on the element's #query property.
+ *
+ * This function can be used as a #pre_render callback.
  *
  * @see forum_block_view()
  */
diff --git a/core/modules/forum/lib/Drupal/forum/Tests/ForumBlockTest.php b/core/modules/forum/lib/Drupal/forum/Tests/ForumBlockTest.php
index fa2e955..1efaeae 100644
--- a/core/modules/forum/lib/Drupal/forum/Tests/ForumBlockTest.php
+++ b/core/modules/forum/lib/Drupal/forum/Tests/ForumBlockTest.php
@@ -98,7 +98,7 @@ public function testNewForumTopicsBlock() {
   }
 
   /**
-   * Test the "Active forum topics" block.
+   * Tests the "Active forum topics" block.
    */
   public function testActiveForumTopicsBlock() {
     $this->drupalLogin($this->adminUser);
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php
index f1664ca..dee29d3 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php
@@ -12,7 +12,18 @@
  */
 class NodeBlockFunctionalTest extends NodeTestBase {
 
+  /**
+   * An administrative user for testing.
+   *
+   * @var \Drupal\user\Plugin\Core\Entity\User
+   */
   protected $adminUser;
+
+  /**
+   * An unprivileged user for testing.
+   *
+   * @var \Drupal\user\Plugin\Core\Entity\User
+   */
   protected $webUser;
 
   /**
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeBlockTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeBlockTest.php
index e176227..b738129 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeBlockTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeBlockTest.php
@@ -30,7 +30,7 @@ public static function getInfo() {
   function setUp() {
     parent::setUp();
 
-    // Create and login user.
+    // Create a user and log in.
     $admin_user = $this->drupalCreateUser(array('administer blocks'));
     $this->drupalLogin($admin_user);
   }
diff --git a/core/modules/openid/openid.module b/core/modules/openid/openid.module
index aa17768..232b41b 100644
--- a/core/modules/openid/openid.module
+++ b/core/modules/openid/openid.module
@@ -130,6 +130,8 @@ function openid_user_logout($account) {
  * Implements hook_block_view_MODULE_DELTA_alter().
  *
  * Adds the OpenID login form to the user login block.
+ *
+ * @see \Drupal\user\Plugin\block\block\UserLoginBlock
  */
 function openid_block_view_user_login_block_alter(&$build, $block) {
   // Only alter the block when it is non-empty, i.e. when no user is logged in.
diff --git a/core/modules/poll/lib/Drupal/poll/Tests/PollBlockTest.php b/core/modules/poll/lib/Drupal/poll/Tests/PollBlockTest.php
index 06a9f1c..49fa169 100644
--- a/core/modules/poll/lib/Drupal/poll/Tests/PollBlockTest.php
+++ b/core/modules/poll/lib/Drupal/poll/Tests/PollBlockTest.php
@@ -12,6 +12,11 @@
  */
 class PollBlockTest extends PollTestBase {
 
+  /**
+   * An administrative user for testing.
+   *
+   * @var Drupal\user\Plugin\Core\Entity\User
+   */
   protected $adminUser;
 
   /**
@@ -33,8 +38,8 @@ function setUp() {
     parent::setUp();
 
     // Create and login user
-    $adminUser = $this->drupalCreateUser(array('administer blocks'));
-    $this->drupalLogin($adminUser);
+    $this->adminUser = $this->drupalCreateUser(array('administer blocks'));
+    $this->drupalLogin($this->adminUser);
   }
 
   /**
diff --git a/core/modules/statistics/statistics.module b/core/modules/statistics/statistics.module
index f7a6c23..2142be4 100644
--- a/core/modules/statistics/statistics.module
+++ b/core/modules/statistics/statistics.module
@@ -410,6 +410,9 @@ function statistics_library_info() {
 
 /**
  * Implements hook_block_alter().
+ *
+ * Removes the "popular" block from display if the module is not configured
+ * to count content views.
  */
 function statistics_block_alter(&$definitions) {
   $statistics_count_content_views = config('statistics.settings')->get('count_content_views');
diff --git a/core/modules/system/lib/Drupal/system/Plugin/PluginUIBase.php b/core/modules/system/lib/Drupal/system/Plugin/PluginUIBase.php
index 205fd56..54afffd 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/PluginUIBase.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/PluginUIBase.php
@@ -11,8 +11,9 @@
 use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
 
 /**
- * An abstract base class for use in creating sane default user interfaces for
- * plugins of a particular type.
+ * Provides defaults for creating user interfaces for plugins of a given type.
+ *
+ * @todo This class needs more documetation and/or @see references.
  */
 abstract class PluginUIBase extends PluginBase implements PluginUIInterface {
 
@@ -50,8 +51,7 @@ public function formSubmit($form, &$form_state) {
   }
 
   /**
-   * Allows a given plugin to exclude various defintions form the user
-   * interface via whatever criteria make sense for that plugin.
+   * Allows a plugin to exclude certain defintions form the user interface.
    *
    * @param array $definitions
    *   The plugin definitions provided by the plugin manager that this user
@@ -65,7 +65,7 @@ protected function excludeDefinitions(array $definitions) {
   }
 
   /**
-   * Generic access check for use with plugins of this type.
+   * Checks access for plugins of this type.
    *
    * @return bool
    *   Returns TRUE if plugins of this type can be accessed.
@@ -76,8 +76,7 @@ public function access() {
   }
 
   /**
-   * A customized row method for displaying plugins for configuration within
-   * the user interface.
+   * Displays a plugin row for configuring plugins in the user interface.
    *
    * @param string $display_plugin_id
    *   The ID of the specific plugin definition being passed to us.
diff --git a/core/modules/system/lib/Drupal/system/Plugin/PluginUIInterface.php b/core/modules/system/lib/Drupal/system/Plugin/PluginUIInterface.php
index 1a95690..9bc7629 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/PluginUIInterface.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/PluginUIInterface.php
@@ -8,12 +8,14 @@
 namespace Drupal\system\Plugin;
 
 /**
- * Interface definition for Plugin UI plugins.
+ * Defines an interface for Plugin UI plugins.
+ *
+ * @todo This needs a lot more explanation.
  */
 interface PluginUIInterface {
 
   /**
-   * Create a form array.
+   * Creates a form array.
    *
    * @param array $form
    *   An associative array containing the structure of the form.
@@ -22,6 +24,8 @@
    *
    * @return array
    *   Returns the form structure as an array.
+   *
+   * @todo Creates a form array for what?
    */
   public function form($form, &$form_state);
 
diff --git a/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php b/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php
index a8f59bd..28725f4 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php
@@ -16,6 +16,8 @@
 
 /**
  * Manages discovery and instantiation of Plugin UI plugins.
+ *
+ * @todo This class needs @see references and/or more documentation.
  */
 class PluginUIManager extends PluginManagerBase {
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
index c7f87c4..b881393 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/TrailTest.php
@@ -43,7 +43,6 @@ function setUp() {
     );
     $this->drupalPost("admin/structure/block/manage/system_menu_block:menu-tools/{$default_theme}", $block, t('Save block'));
 
-
     // This test puts menu links in the Administration menu and then tests for
     // their presence on the page, so we need to ensure that the Administration
     // block will be displayed in the default theme.
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 36154c5..2dbbcd7 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1123,6 +1123,9 @@ function system_menu() {
 
 /**
  * Proxies to the plugin class' form method.
+ *
+ * @todo This needs more explanation, an @see or two, and parameter
+ *   documentation. Also "proxies" is a weird word to use.
  */
 function system_plugin_ui_form($form, &$form_state, $plugin, $facet = NULL) {
   $plugin_ui = drupal_container()->get('plugin.manager.system.plugin_ui')->createInstance($plugin);
@@ -1133,7 +1136,9 @@ function system_plugin_ui_form($form, &$form_state, $plugin, $facet = NULL) {
 }
 
 /**
- * Page callback: Autocomplete any plugin system tied to a plugin UI plugin.
+ * Page callback: Autocompletes any plugin system tied to a plugin UI plugin.
+ *
+ * @todo This needs more explanation and parameter documentation.
  */
 function system_plugin_autocomplete($plugin_id, $string = '') {
   $matches = array();
@@ -1151,7 +1156,10 @@ function system_plugin_autocomplete($plugin_id, $string = '') {
 }
 
 /**
- * A simple wrapper function for proxying to the plugin class' access method.
+ * Checks access for a given plugin using the plugin's access() method.
+ *
+ * @todo This needs more explanation, some @see, and parameter documentation.
+ * @todo What the heck kind of parameter name is "facet"?
  */
 function system_plugin_ui_access($plugin, $facet = NULL) {
   $plugin_ui = drupal_container()->get('plugin.manager.system.plugin_ui')->createInstance($plugin);
diff --git a/core/modules/system/system.plugin.ui.css b/core/modules/system/system.plugin.ui.css
index 207a6ee..c932788 100644
--- a/core/modules/system/system.plugin.ui.css
+++ b/core/modules/system/system.plugin.ui.css
@@ -26,4 +26,4 @@
 #block-library .bottom-bar {
   width:100%;
   clear:both;
-}
\ No newline at end of file
+}
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
index 668187e..89b9131 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserNewBlock.php
@@ -65,7 +65,7 @@ public function configureSubmit($form, &$form_state) {
    * Overrides \Drupal\block\BlockBase::build().
    */
   public function build() {
-    // Retrieve a list of new users who have subsequently accessed the site successfully.
+    // Retrieve a list of new users who have accessed the site successfully.
     $items = db_query_range('SELECT uid, name FROM {users} WHERE status <> 0 AND access <> 0 ORDER BY created DESC', 0, $this->configuration['whois_new_count'])->fetchAll();
     $build = array(
       '#theme' => 'item_list__user__new',
diff --git a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
index d3138b3..1253c71 100644
--- a/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
+++ b/core/modules/user/lib/Drupal/user/Plugin/block/block/UserOnlineBlock.php
@@ -14,6 +14,9 @@
 /**
  * Provides a "Who's online" block.
  *
+ * @todo Move this block to the Statistics module and remove its dependency on
+ *   user_access().
+ *
  * @Plugin(
  *   id = "user_online_block",
  *   subject = @Translation("Who's online"),
@@ -74,9 +77,6 @@ public function configureSubmit($form, &$form_state) {
 
   /**
    * Overrides \Drupal\block\BlockBase::build().
-   *
-   * @todo Move this block to statistics.module and remove dependency on
-   *   user.access.
    */
   public function build() {
     // Count users active within the defined period.
diff --git a/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsBlock.php b/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsBlock.php
index 45db464..16ddf4a 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsBlock.php
@@ -37,7 +37,7 @@ public function getDerivativeDefinition($derivative_id, array $base_plugin_defin
    */
   public function getDerivativeDefinitions(array $base_plugin_definition) {
     foreach (views_get_all_views() as $view) {
-      // disabled views get nothing.
+      // Do not return results for disabled views.
       if (!$view->isEnabled()) {
         continue;
       }
diff --git a/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsExposedFilterBlock.php b/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsExposedFilterBlock.php
index f0408f9..02180ec 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsExposedFilterBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/Derivative/ViewsExposedFilterBlock.php
@@ -37,7 +37,7 @@ public function getDerivativeDefinition($derivative_id, array $base_plugin_defin
    */
   public function getDerivativeDefinitions(array $base_plugin_definition) {
     foreach (views_get_all_views() as $view) {
-      // disabled views get nothing.
+      // Do not return results for disabled views.
       if (!$view->isEnabled()) {
         continue;
       }
diff --git a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
index d35fe36..835978a 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/block/block/ViewsExposedFilterBlock.php
@@ -28,8 +28,8 @@ class ViewsExposedFilterBlock extends ViewsBlock {
   public function build() {
     $type = 'exp';
     $output = $this->view->display_handler->viewSpecialBlocks($type);
-    // Before returning the block output, convert it to a renderable
-    // array with contextual links.
+    // Before returning the block output, convert it to a renderable array with
+    // contextual links.
     views_add_block_contextual_links($output, $this->view, $this->display_id, 'special_block_' . $type);
     $this->view->destroy();
     return $output;
diff --git a/core/modules/views/lib/Drupal/views/Tests/UI/OverrideDisplaysTest.php b/core/modules/views/lib/Drupal/views/Tests/UI/OverrideDisplaysTest.php
index 193f0fb..1182a40 100644
--- a/core/modules/views/lib/Drupal/views/Tests/UI/OverrideDisplaysTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/UI/OverrideDisplaysTest.php
@@ -67,8 +67,8 @@ function testOverrideDisplays() {
     $this->drupalGet('');
     $this->assertText($original_title);
 
-    // Change the title for the page display only, and make sure that the original title
-    // still appears on the page.
+    // Change the title for the page display only, and make sure that the
+    // original title still appears on the page.
     $edit = array();
     $edit['title'] = $new_title = $this->randomName(16);
     $edit['override[dropdown]'] = 'page_1';
diff --git a/core/profiles/standard/standard.install b/core/profiles/standard/standard.install
index 784b5fd..c5f6d67 100644
--- a/core/profiles/standard/standard.install
+++ b/core/profiles/standard/standard.install
@@ -75,116 +75,6 @@ function standard_install() {
   theme_enable(array($default_theme));
   theme_disable(array('stark'));
 
-  // Enable some standard blocks.
-  //$admin_theme = 'seven';
-  //$blocks = array(
-    //array(
-      //'module' => 'system',
-      //'delta' => 'main',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'content',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'search',
-      //'delta' => 'form',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => -1,
-      //'region' => 'sidebar_first',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'user',
-      //'delta' => 'login',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'sidebar_first',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'system',
-      //'delta' => 'menu-tools',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'sidebar_first',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'system',
-      //'delta' => 'menu-footer',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'footer',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'system',
-      //'delta' => 'powered-by',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => 10,
-      //'region' => 'footer',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'system',
-      //'delta' => 'help',
-      //'theme' => $default_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'help',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'system',
-      //'delta' => 'main',
-      //'theme' => $admin_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'content',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'system',
-      //'delta' => 'help',
-      //'theme' => $admin_theme,
-      //'status' => 1,
-      //'weight' => 0,
-      //'region' => 'help',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-    //array(
-      //'module' => 'user',
-      //'delta' => 'login',
-      //'theme' => $admin_theme,
-      //'status' => 1,
-      //'weight' => 10,
-      //'region' => 'content',
-      //'pages' => '',
-      //'cache' => -1,
-    //),
-  //);
-  //$query = db_insert('block')->fields(array('module', 'delta', 'theme', 'status', 'weight', 'region', 'pages', 'cache'));
-  //foreach ($blocks as $block) {
-    //$query->values($block);
-  //}
-  //$query->execute();
-
   // Set front page to "node".
   config('system.site')->set('page.front', 'node')->save();