diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 9820348e66b1..8eeb57f00550 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -61,14 +61,14 @@ function block_help($path, $arg) {
       $output .= '<dd>' . t('Blocks can be configured to be visible only on certain pages, only to users of certain roles, or only on pages displaying certain <a href="@content-type">content types</a>. Some dynamic blocks, such as those generated by modules, will be displayed only on certain pages.', array('@content-type' => url('admin/structure/types'), '@user' => url('user'))) . '</dd>';
       if (module_exists('custom_block')) {
         $output .= '<dt>' . t('Creating custom blocks') . '</dt>';
-        $output .= '<dd>' . t('Users with the <em>Administer blocks</em> permission can <a href="@block-add">add custom blocks</a>, which are then listed on the <a href="@blocks">Blocks administration page</a>. Once created, custom blocks behave just like default and module-generated blocks.', array('@blocks' => url('admin/structure/block'), '@block-add' => url('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add/custom_blocks'))) . '</dd>';
+        $output .= '<dd>' . t('Users with the <em>Administer blocks</em> permission can <a href="@block-add">add custom blocks</a>, which are then listed on the <a href="@blocks">Blocks administration page</a>. Once created, custom blocks behave just like default and module-generated blocks.', array('@blocks' => url('admin/structure/block'), '@block-add' => url('admin/structure/block/list/' . config('system.theme')->get('default') . '/add/custom_blocks'))) . '</dd>';
       }
       $output .= '</dl>';
       return $output;
   }
   if ($arg[0] == 'admin' && $arg[1] == 'structure' && $arg['2'] == 'block' && (empty($arg[3]) || $arg[3] == 'list') && empty($arg[5])) {
     if (!empty($arg[4])) {
-      list(, $demo_theme) = explode(':', $arg[4]);
+      $demo_theme = $arg[4];
     }
     else {
       $demo_theme = config('system.theme')->get('default');
@@ -136,28 +136,28 @@ function block_menu() {
   //   and plugin IDs to decouple the routes from these dependencies and allow
   //   hook_menu_local_tasks() to check for the untranslated tab_parent path.
   // @see http://drupal.org/node/1067408
-  $themes = list_themes();
-  foreach (drupal_container()->get('plugin.manager.system.plugin_ui')->getDefinitions() as $plugin_id => $plugin) {
-    list($plugin_base, $key) = explode(':', $plugin_id);
-    if ($plugin_base == 'block_plugin_ui') {
-      $theme = $themes[$key];
-      $items['admin/structure/block/list/' . $plugin_id] = array(
-        'title' => check_plain($theme->info['name']),
-        'type' => $key == $default_theme ? MENU_DEFAULT_LOCAL_TASK : MENU_LOCAL_TASK,
-        'route_name' => 'block_admin_display.' . $plugin_id
-      );
-      $items['admin/structure/block/demo/' . $key] = array(
-        'title' => check_plain($theme->info['name']),
-        'page callback' => 'block_admin_demo',
-        'page arguments' => array($key),
-        'type' => MENU_CALLBACK,
-        'access callback' => '_block_themes_access',
-        'access arguments' => array($key),
-        'theme callback' => '_block_custom_theme',
-        'theme arguments' => array($key),
-        'file' => 'block.admin.inc',
-      );
-    }
+  foreach (list_themes() as $key => $theme) {
+    $items["admin/structure/block/list/$key"] = array(
+      'title' => check_plain($theme->info['name']),
+      'type' => $key == $default_theme ? MENU_DEFAULT_LOCAL_TASK : MENU_LOCAL_TASK,
+      'route_name' => "block_admin_display.$key",
+    );
+    $items["admin/structure/block/list/$key/add"] = array(
+      'title' => 'Place blocks',
+      'type' => MENU_LOCAL_ACTION,
+      'route_name' => "block_plugin_ui.$key",
+    );
+    $items["admin/structure/block/demo/$key"] = array(
+      'title' => check_plain($theme->info['name']),
+      'page callback' => 'block_admin_demo',
+      'page arguments' => array($key),
+      'type' => MENU_CALLBACK,
+      'access callback' => '_block_themes_access',
+      'access arguments' => array($key),
+      'theme callback' => '_block_custom_theme',
+      'theme arguments' => array($key),
+      'file' => 'block.admin.inc',
+    );
   }
   return $items;
 }
diff --git a/core/modules/block/block.routing.yml b/core/modules/block/block.routing.yml
index cabd4cbc1482..669e0a21239a 100644
--- a/core/modules/block/block.routing.yml
+++ b/core/modules/block/block.routing.yml
@@ -26,3 +26,10 @@ block_admin_add:
     _content: '\Drupal\block\Controller\BlockAddController::blockAddConfigureForm'
   requirements:
     _permission: 'administer blocks'
+
+block_autocomplete:
+  pattern: '/block/autocomplete'
+  defaults:
+    _controller: '\Drupal\block\Controller\BlockAutocompleteController::autocomplete'
+  requirements:
+    _permission: 'administer blocks'
diff --git a/core/modules/block/block.services.yml b/core/modules/block/block.services.yml
index 9b6b40d0e2a9..b361dba6b3e6 100644
--- a/core/modules/block/block.services.yml
+++ b/core/modules/block/block.services.yml
@@ -13,7 +13,6 @@ services:
     class: Drupal\block\Routing\RouteSubscriber
     tags:
       - { name: event_subscriber}
-    arguments: ['@plugin.manager.system.plugin_ui']
   block.theme_access_check:
     class: Drupal\block\Access\BlockThemeAccessCheck
     tags:
diff --git a/core/modules/block/lib/Drupal/block/BlockFormController.php b/core/modules/block/lib/Drupal/block/BlockFormController.php
index 0386277e0449..6041b2c99f70 100644
--- a/core/modules/block/lib/Drupal/block/BlockFormController.php
+++ b/core/modules/block/lib/Drupal/block/BlockFormController.php
@@ -283,7 +283,7 @@ class BlockFormController extends EntityFormController implements EntityControll
 
     drupal_set_message(t('The block configuration has been saved.'));
     cache_invalidate_tags(array('content' => TRUE));
-    $form_state['redirect'] = 'admin/structure/block/list/block_plugin_ui:' . $entity->get('theme');
+    $form_state['redirect'] = 'admin/structure/block/list/' . $entity->get('theme');
   }
 
   /**
diff --git a/core/modules/block/lib/Drupal/block/Controller/BlockAutocompleteController.php b/core/modules/block/lib/Drupal/block/Controller/BlockAutocompleteController.php
new file mode 100644
index 000000000000..539a8c193d91
--- /dev/null
+++ b/core/modules/block/lib/Drupal/block/Controller/BlockAutocompleteController.php
@@ -0,0 +1,78 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\block\Controller\BlockAutocompleteController.
+ */
+
+namespace Drupal\block\Controller;
+
+use Drupal\Component\Plugin\PluginManagerInterface;
+use Drupal\Component\Utility\Tags;
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Controller\ControllerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\HttpFoundation\JsonResponse;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Provides an autocomplete for blocks.
+ */
+class BlockAutocompleteController implements ControllerInterface {
+
+  /**
+   * The block plugin manager.
+   *
+   * @var \Drupal\Component\Plugin\PluginManagerInterface
+   */
+  protected $manager;
+
+  /**
+   * Constructs a new BlockAutocompleteController object.
+   *
+   * @param \Drupal\Component\Plugin\PluginManagerInterface $manager
+   *   The block plugin manager.
+   */
+  public function __construct(PluginManagerInterface $manager) {
+    $this->manager = $manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('plugin.manager.block')
+    );
+  }
+
+  /**
+   * Autocompletes a block plugin ID.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The request object.
+   *
+   * @return \Symfony\Component\HttpFoundation\JsonResponse
+   *   The matched plugins as JSON.
+   */
+  public function autocomplete(Request $request) {
+    $string_typed = $request->query->get('q');
+    // The passed string may be comma or space separated.
+    $string_typed = Tags::explode($string_typed);
+    // Take the last result and lowercase it.
+    $string = Unicode::strtolower(array_pop($string_typed));
+    $matches = array();
+    if ($string) {
+      $titles = array();
+      // Gather all block plugins and their admin titles.
+      foreach($this->manager->getDefinitions() as $plugin_id => $plugin) {
+        $titles[$plugin_id] = $plugin['admin_label'];
+      }
+      // Find any matching block plugin IDs.
+      $matches = preg_grep("/\b". $string . "/i", $titles);
+    }
+
+    return new JsonResponse($matches);
+  }
+
+}
diff --git a/core/modules/block/lib/Drupal/block/Controller/BlockListController.php b/core/modules/block/lib/Drupal/block/Controller/BlockListController.php
index 832aaedea329..f31e652527d0 100644
--- a/core/modules/block/lib/Drupal/block/Controller/BlockListController.php
+++ b/core/modules/block/lib/Drupal/block/Controller/BlockListController.php
@@ -18,17 +18,15 @@ class BlockListController extends EntityListController {
   /**
    * Shows the block administration page.
    *
-   * @param string $entity_type
-   *   Entity type of list page.
    * @param string|null $theme
    *   Theme key of block list.
    *
    * @return array
    *   A render array as expected by drupal_render().
    */
-  public function listing($entity_type, $theme = NULL) {
-    $default_theme = $theme ?: $this->config('system.theme')->get('default');
-    return $this->entityManager()->getListController($entity_type)->render($default_theme);
+  public function listing($theme = NULL) {
+    $theme = $theme ?: $this->config('system.theme')->get('default');
+    return $this->entityManager()->getListController('block')->render($theme);
   }
 
 }
diff --git a/core/modules/block/lib/Drupal/block/Form/PlaceBlocksForm.php b/core/modules/block/lib/Drupal/block/Form/PlaceBlocksForm.php
new file mode 100644
index 000000000000..ffc4b9ef695c
--- /dev/null
+++ b/core/modules/block/lib/Drupal/block/Form/PlaceBlocksForm.php
@@ -0,0 +1,157 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\block\Form\PlaceBlocksForm.
+ */
+
+namespace Drupal\block\Form;
+
+use Drupal\Component\Plugin\PluginManagerInterface;
+use Drupal\Component\Utility\String;
+use Drupal\Core\Controller\ControllerInterface;
+use Drupal\Core\Form\FormInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Provides the 'Place blocks' form.
+ */
+class PlaceBlocksForm implements FormInterface, ControllerInterface {
+
+  /**
+   * The block plugin manager.
+   *
+   * @var \Drupal\Component\Plugin\PluginManagerInterface
+   */
+  protected $manager;
+
+  /**
+   * The theme this block will be placed into.
+   *
+   * @var string
+   */
+  protected $theme;
+
+  /**
+   * Constructs a new PlaceBlocksForm object.
+   *
+   * @param \Drupal\Component\Plugin\PluginManagerInterface $manager
+   *   The block plugin manager.
+   */
+  public function __construct(PluginManagerInterface $manager) {
+    $this->manager = $manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('plugin.manager.block')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormID() {
+    return 'block_plugin_ui';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state, $theme = NULL, $category = NULL) {
+    $this->theme = $theme;
+    $form['#theme'] = 'system_plugin_ui_form';
+    $rows = array();
+    $categories = array();
+    foreach ($this->manager->getDefinitions() as $plugin_id => $plugin_definition) {
+      if (empty($category) || $plugin_definition['category'] == $category) {
+        $rows[$plugin_id] = $this->row($plugin_id, $plugin_definition);
+      }
+      $categories[$plugin_definition['category']] = array(
+        'title' => $plugin_definition['category'],
+        'href' => 'admin/structure/block/list/' . $this->theme . '/add/' . $plugin_definition['category'],
+      );
+    }
+
+    $form['right']['block'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Search'),
+      '#autocomplete_path' => 'block/autocomplete',
+    );
+    $form['right']['submit'] = array(
+      '#type' => 'submit',
+      '#button_type' => 'primary',
+      '#value' => t('Next'),
+    );
+    $form['right']['all_plugins'] = array(
+      '#type' => 'link',
+      '#title' => t('All blocks'),
+      '#href' => 'admin/structure/block/list/' . $this->theme . '/add',
+    );
+    if (!empty($categories)) {
+      $form['right']['categories'] = array(
+        '#theme' => 'links',
+        '#heading' => array(
+          'text' => t('Categories'),
+          'level' => 'h3',
+        ),
+        '#links' => $categories,
+      );
+    }
+
+    // Sort rows alphabetically.
+    asort($rows);
+    $form['left']['plugin_library'] = array(
+      '#theme' => 'table',
+      '#header' => array(t('Subject'), t('Operations')),
+      '#rows' => $rows,
+    );
+    return $form;
+  }
+
+  /**
+   * Generates the row data for a single block plugin.
+   *
+   * @param string $plugin_id
+   *   The plugin ID.
+   * @param array $plugin_definition
+   *   The plugin definition.
+   *
+   * @return array
+   *   The row data for a single block plugin.
+   */
+  protected function row($plugin_id, array $plugin_definition) {
+    $row = array();
+    $row[] = String::checkPlain($plugin_definition['admin_label']);
+    $row[] = array('data' => array(
+      '#type' => 'operations',
+      '#links' => array(
+        'configure' => array(
+          'title' => t('Place block'),
+          'href' => 'admin/structure/block/add/' . $plugin_id . '/' . $this->theme,
+        ),
+      ),
+    ));
+    return $row;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, array &$form_state) {
+    if (!$this->manager->getDefinition($form_state['values']['block'])) {
+      form_set_error('block', t('You must select a valid block.'));
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    $form_state['redirect'] = 'admin/structure/block/add/' . $form_state['values']['block'] . '/' . $this->theme;
+  }
+
+}
diff --git a/core/modules/block/lib/Drupal/block/Plugin/Derivative/BlockPluginUI.php b/core/modules/block/lib/Drupal/block/Plugin/Derivative/BlockPluginUI.php
deleted file mode 100644
index aaeef6e2b1b2..000000000000
--- a/core/modules/block/lib/Drupal/block/Plugin/Derivative/BlockPluginUI.php
+++ /dev/null
@@ -1,29 +0,0 @@
-<?php
-
-/**
- * Contains \Drupal\block\Plugin\Derivative\BlockPluginUI.
- */
-
-namespace Drupal\block\Plugin\Derivative;
-
-use Drupal\Component\Plugin\Derivative\DerivativeBase;
-
-/**
- * Provides block plugin UI plugin definitions for all themes.
- *
- * @todo Add documentation to this class.
- *
- * @see \Drupal\block\Plugin\system\plugin_ui\BlockPluginUI
- */
-class BlockPluginUI extends DerivativeBase {
-  /**
-   * {@inheritdoc}
-   */
-  public function getDerivativeDefinitions(array $base_plugin_definition) {
-    // Provide a derivative of the plugin UI for each theme.
-    foreach (list_themes() as $key => $theme) {
-      $this->derivatives[$key] = $base_plugin_definition;
-    }
-    return parent::getDerivativeDefinitions($base_plugin_definition);
-  }
-}
diff --git a/core/modules/block/lib/Drupal/block/Plugin/PluginUI/BlockPluginUI.php b/core/modules/block/lib/Drupal/block/Plugin/PluginUI/BlockPluginUI.php
deleted file mode 100644
index de7e0791087a..000000000000
--- a/core/modules/block/lib/Drupal/block/Plugin/PluginUI/BlockPluginUI.php
+++ /dev/null
@@ -1,229 +0,0 @@
-<?php
-
-/**
- * Contains \Drupal\block\Plugin\PluginUI\BlockPluginUI.
- */
-
-namespace Drupal\block\Plugin\PluginUI;
-
-use Drupal\system\Plugin\PluginUIBase;
-use Drupal\Component\Annotation\Plugin;
-use Drupal\Core\Annotation\Translation;
-
-/**
- * Defines an overrideable UI for block selection, configuration, and placement.
- *
- * @Plugin(
- *   id = "block_plugin_ui",
- *   module = "block",
- *   all_plugins = @Translation("All Blocks"),
- *   config_path = "admin/structure/block/add",
- *   default_task = TRUE,
- *   derivative = "Drupal\block\Plugin\Derivative\BlockPluginUI",
- *   facets = {
- *     "module" = @Translation("Modules")
- *   },
- *   link_title = @Translation("Place block"),
- *   manager = "plugin.manager.block",
- *   menu = TRUE,
- *   path = "admin/structure/block/list",
- *   suffix = "add",
- *   task_suffix = "library",
- *   task_title = @Translation("Library"),
- *   title = @Translation("Place blocks"),
- *   title_attribute = "admin_label",
- *   type = MENU_LOCAL_ACTION
- * )
- */
-class BlockPluginUI extends PluginUIBase {
-
-  /**
-   * Overrides \Drupal\system\Plugin\PluginUIBase::form().
-   *
-   * @todo Add inline documentation to this method.
-   */
-  public function form($form, &$form_state, $facet = NULL) {
-    // @todo Add an inline comment here.
-    list($plugin, $theme) = explode(':', $this->getPluginId());
-    $plugin_definition = $this->getPluginDefinition();
-    // @todo Find out how to let the manager be injected into the class.
-    $manager = drupal_container()->get($plugin_definition['manager']);
-    $plugins = $manager->getDefinitions();
-    $form['#theme'] = 'system_plugin_ui_form';
-    $form['theme'] = array(
-      '#type' => 'value',
-      '#value' => $theme,
-    );
-    $form['manager'] = array(
-      '#type' => 'value',
-      '#value' => $manager,
-    );
-    $form['instance'] = array(
-      '#type' => 'value',
-      '#value' => $this,
-    );
-    $form['right']['block'] = array(
-      '#type' => 'textfield',
-      '#title' => t('Search'),
-      '#autocomplete_path' => 'system/autocomplete/' . $this->getPluginId(),
-    );
-    $form['right']['submit'] = array(
-      '#type' => 'submit',
-      '#value' => t('Next'),
-    );
-    $rows = array();
-    foreach ($plugins as $plugin_id => $display_plugin_definition) {
-      if (empty($facet) || $this->facetCompare($facet, $display_plugin_definition)) {
-        $rows[$plugin_id] = $this->row($plugin_id, $display_plugin_definition);
-      }
-      foreach ($plugin_definition['facets'] as $key => $title) {
-        $facets[$key][$display_plugin_definition[$key]] = $this->facetLink($key, $plugin_id, $display_plugin_definition);
-      }
-      $form['right']['all_plugins'] = array(
-        '#type' => 'link',
-        '#title' => $plugin_definition['all_plugins'],
-        '#href' => $this->allPluginsUrl($plugin_id, $display_plugin_definition),
-      );
-      foreach ($facets as $group => $values) {
-        $form['right'][$group] = array(
-          '#theme' => 'links',
-          '#heading' => array(
-            'text' => $plugin_definition['facets'][$group],
-            'level' => 'h3',
-          ),
-          '#links' => $values,
-        );
-      }
-    }
-    // Sort rows alphabetically.
-    asort($rows);
-    $form['left']['plugin_library'] = array(
-      '#theme' => 'table',
-      '#header' => $this->tableHeader(),
-      '#rows' => $rows,
-    );
-    return $form;
-  }
-
-  /**
-   * Overrides \Drupal\system\Plugin\PluginUIBase::formValidate().
-   */
-  public function formValidate($form, &$form_state) {
-    $definitions = $form_state['values']['manager']->getDefinitions();
-    if (!isset($definitions[$form_state['values']['block']])) {
-      form_set_error('block', t('You must select a valid block.'));
-    }
-  }
-
-  /**
-   * Overrides \Drupal\system\Plugin\PluginUIBase::formSubmit().
-   */
-  public function formSubmit($form, &$form_state) {
-    $form_state['redirect'] = 'admin/structure/block/add/' . $form_state['values']['block'] . '/' . $form_state['values']['theme'];
-  }
-
-  /**
-   * Overrides \Drupal\system\Plugin\PluginUIBase::access().
-   */
-  public function access() {
-    list($plugin, $theme) = explode(':', $this->getPluginId());
-    return _block_themes_access($theme);
-  }
-
-  /**
-   * Overrides \Drupal\system\Plugin\PluginUIBase::tableHeader().
-   */
-  public function tableHeader() {
-    return array(t('Subject'), t('Operations'));
-  }
-
-  /**
-   * Overrides \Drupal\system\Plugin\PluginUIBase::row().
-   */
-  public function row($display_plugin_id, array $display_plugin_definition) {
-    $plugin_definition = $this->getPluginDefinition();
-    list($plugin, $theme) = explode(':', $this->getPluginId());
-    $row = array();
-    $row[] = check_plain($display_plugin_definition['admin_label']);
-    $row[] = array('data' => array(
-      '#type' => 'operations',
-      '#links' => array(
-        'configure' => array(
-          'title' => $plugin_definition['link_title'],
-          'href' => $plugin_definition['config_path'] . '/' . $display_plugin_id . '/' . $theme,
-        ),
-      ),
-    ));
-    return $row;
-  }
-
-  /**
-   * Creates a facet link for a given facet of a display plugin.
-   *
-   * Provides individually formatted links for the faceting that happens within
-   * the user interface. Since this is a faceting style procedure, each plugin
-   * may be parsed multiple times in order to extract all facets and their
-   * appropriate labels.
-   *
-   * The $display_plugin_id and $display_plugin_definition are provided for
-   * convenience when overriding this method.
-   *
-   * @param string $facet
-   *   A simple string indicating what element of the $display_plugin_definition
-   *   to utilize for faceting.
-   * @param string $display_plugin_id
-   *   The plugin ID of the plugin we are currently parsing a facet link from.
-   * @param array $display_plugin_definition
-   *   The plugin definition we are parsing.
-   *
-   * @return array
-   *   Returns a row array comaptible with theme_links().
-   */
-  protected function facetLink($facet, $display_plugin_id, array $display_plugin_definition) {
-    $plugin_definition = $this->getPluginDefinition();
-    return array(
-      'title' => $display_plugin_definition[$facet],
-      'href' => $plugin_definition['path'] . '/' . $this->getPluginId() . '/' . $facet . ':' . $display_plugin_definition[$facet],
-    );
-  }
-
-  /**
-   * Determines whether a given facet should be displayed for a plugin.
-   *
-   * Compares a given plugin definition with the selected facet to determine if
-   * the plugin should be displayed in the user interface.
-   *
-   * @param string $facet
-   *   A colon separated string representing the key/value paring of a selected
-   *   facet.
-   * @param array $display_plugin_definition
-   *   The plugin definition to be compared.
-   *
-   * @return bool
-   *   Returns TRUE if the selected facet matches this plugin.
-   */
-  protected function facetCompare($facet, $display_plugin_definition) {
-    list($facet_type, $option) = explode(':', $facet);
-    return $option == $display_plugin_definition[$facet_type];
-  }
-
-  /**
-   * Provides an "all" style link to reset the facets.
-   *
-   * The $display_plugin_id and $display_plugin_definition are provided for
-   * convenience when overriding this method.
-   *
-   * @param string $display_plugin_id
-   *   The plugin ID of the plugin we are currently parsing a facet link from.
-   * @param array $display_plugin_definition
-   *   The plugin definition we are parsing.
-   *
-   * @return string
-   *   Returns a simple URL string for use within l().
-   */
-  protected function allPluginsUrl($display_plugin_id, $display_plugin_definition) {
-    $plugin_definition = $this->getPluginDefinition();
-    return $plugin_definition['path'] . '/' . $this->getPluginId() . '/add';
-  }
-
-}
diff --git a/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php b/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php
index 34daaca738f6..7a50351836af 100644
--- a/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php
+++ b/core/modules/block/lib/Drupal/block/Plugin/Type/BlockManager.php
@@ -1,6 +1,7 @@
 <?php
 
 /**
+ * @file
  * Contains \Drupal\block\Plugin\Type\BlockManager.
  */
 
@@ -10,6 +11,7 @@ use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Language\LanguageManager;
 use Drupal\Core\Plugin\DefaultPluginManager;
+
 /**
  * Manages discovery and instantiation of block plugins.
  *
@@ -37,4 +39,17 @@ class BlockManager extends DefaultPluginManager {
     $this->alterInfo($module_handler, 'block');
     $this->setCacheBackend($cache_backend, $language_manager, 'block_plugins');
   }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function processDefinition(&$definition, $plugin_id) {
+    parent::processDefinition($definition, $plugin_id);
+
+    // Ensure that every block has a category.
+    $definition += array(
+      'category' => $definition['provider'],
+    );
+  }
+
 }
diff --git a/core/modules/block/lib/Drupal/block/Routing/RouteSubscriber.php b/core/modules/block/lib/Drupal/block/Routing/RouteSubscriber.php
index deea1f4018d8..de32cd162728 100644
--- a/core/modules/block/lib/Drupal/block/Routing/RouteSubscriber.php
+++ b/core/modules/block/lib/Drupal/block/Routing/RouteSubscriber.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file
  * Contains \Drupal\block\Routing\RouteSubscriber.
@@ -11,31 +12,12 @@ use Drupal\Core\Routing\RoutingEvents;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Drupal\Component\Plugin\PluginManagerInterface;
 
 /**
  * Listens to the dynamic route events.
  */
 class RouteSubscriber implements EventSubscriberInterface {
 
-  /**
-   * The injection plugin manager that should be passed into the route.
-   *
-   * @var \Drupal\Component\Plugin\PluginManagerInterface
-   */
-  protected $pluginManager;
-
-
-  /**
-   * Constructs a RouteSubscriber object.
-   *
-   * @param \Drupal\Component\Plugin\PluginManagerInterface $plugin_manager
-   *   The service container this object should use.
-   */
-  public function __construct(PluginManagerInterface $plugin_manager) {
-    $this->pluginManager = $plugin_manager;
-  }
-
   /**
    * Implements EventSubscriberInterface::getSubscribedEvents().
    */
@@ -55,18 +37,32 @@ class RouteSubscriber implements EventSubscriberInterface {
    */
   public function routes(RouteBuildEvent $event) {
     $collection = $event->getRouteCollection();
-    foreach ($this->pluginManager->getDefinitions() as $plugin_id => $plugin) {
-      list($plugin_base, $key) = explode(':', $plugin_id);
-      if ($plugin_base == 'block_plugin_ui') {
-        $route = new Route('admin/structure/block/list/' . $plugin_id, array(
+    foreach (list_themes(TRUE) as $key => $theme) {
+      // The block entity listing page.
+      $route = new Route(
+        "admin/structure/block/list/$key",
+        array(
           '_controller' => '\Drupal\block\Controller\BlockListController::listing',
-          'entity_type' => 'block',
           'theme' => $key,
-        ), array(
+        ),
+        array(
           '_block_themes_access' => 'TRUE',
-        ));
-        $collection->add('block_admin_display.' . $plugin_id, $route);
-      }
+        )
+      );
+      $collection->add("block_admin_display.$key", $route);
+
+      // The block plugin listing page.
+      $route = new Route(
+        "admin/structure/block/list/$key/add/{category}",
+        array(
+          '_form' => '\Drupal\block\Form\PlaceBlocksForm',
+          'category' => NULL,
+          'theme' => $key,
+        ),
+        array('_block_themes_access' => 'TRUE')
+      );
+      $collection->add("block_plugin_ui.$key", $route);
     }
   }
+
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
index 8c64ac879ba1..c3a220f4d4db 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockAdminThemeTest.php
@@ -38,14 +38,14 @@ class BlockAdminThemeTest extends WebTestBase {
     $this->drupalLogin($admin_user);
 
     // Ensure that access to block admin page is denied when theme is disabled.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:bartik');
+    $this->drupalGet('admin/structure/block/list/bartik');
     $this->assertResponse(403);
 
     // Enable admin theme and confirm that tab is accessible.
     theme_enable(array('bartik'));
     $edit['admin_theme'] = 'bartik';
     $this->drupalPost('admin/appearance', $edit, t('Save configuration'));
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:bartik');
+    $this->drupalGet('admin/structure/block/list/bartik');
     $this->assertResponse(200);
   }
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockLibrarySearchTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockLibrarySearchTest.php
index 22f47e8c6b46..8dcfeaa13fe8 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockLibrarySearchTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockLibrarySearchTest.php
@@ -49,11 +49,11 @@ class BlockLibrarySearchTest extends WebTestBase {
    */
   function testBlockLibrarySearch() {
     // Check that the block plugin is valid.
-    $this->drupalPost('admin/structure/block/list/block_plugin_ui:stark/add', array('block' => 'invalid_block'), t('Next'));
+    $this->drupalPost('admin/structure/block/list/stark/add', array('block' => 'invalid_block'), t('Next'));
     $this->assertText('You must select a valid block.');
 
     // Check that the block search form redirects to the correct block form.
-    $this->drupalPost('admin/structure/block/list/block_plugin_ui:stark/add', array('block' => 'system_main_block'), t('Next'));
+    $this->drupalPost('admin/structure/block/list/stark/add', array('block' => 'system_main_block'), t('Next'));
     $this->assertUrl('admin/structure/block/add/system_main_block/stark');
   }
 
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
index e665609d976e..c766053042e9 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
@@ -274,7 +274,7 @@ class BlockTest extends BlockTestBase {
     }
 
     // Ensure that the disabled module's block plugin is no longer available.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add');
+    $this->drupalGet('admin/structure/block/list/' . config('system.theme')->get('default') . '/add');
     $this->assertNoText(t('Test block caching'));
 
     // Confirm that the block is no longer displayed on the front page.
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTitleXSSTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTitleXSSTest.php
index 6562545c527d..3036ecd81ea0 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTitleXSSTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTitleXSSTest.php
@@ -45,7 +45,7 @@ class BlockTitleXSSTest extends WebTestBase {
 
     $this->drupalLogin($this->drupalCreateUser(array('administer blocks', 'access administration pages')));
     $default_theme = config('system.theme')->get('default');
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . $default_theme . '/add');
+    $this->drupalGet('admin/structure/block/list/' . $default_theme . '/add');
     $this->assertNoRaw("<script>alert('XSS subject');</script>", 'The block title was properly sanitized in Block Plugin UI Admin page.');
   }
 
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
index 7ad84e19e891..62d24981a055 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
@@ -110,7 +110,7 @@ class BlockUiTest extends WebTestBase {
    */
   function testBlockSearch() {
     $block = t('Administration');
-    $blocks = drupal_json_decode($this->drupalGet('system/autocomplete/block_plugin_ui:stark', array('query' => array('q' => $block))));
+    $blocks = drupal_json_decode($this->drupalGet('block/autocomplete', array('query' => array('q' => $block))));
     $this->assertEqual($blocks['system_menu_block:menu-admin'], $block, t('Can search for block with name !block.', array('!block' => $block)));
   }
 
diff --git a/core/modules/block/lib/Drupal/block/Tests/NonDefaultBlockAdminTest.php b/core/modules/block/lib/Drupal/block/Tests/NonDefaultBlockAdminTest.php
index 7cf114c877fd..72f3d1d116cb 100644
--- a/core/modules/block/lib/Drupal/block/Tests/NonDefaultBlockAdminTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/NonDefaultBlockAdminTest.php
@@ -34,7 +34,7 @@ class NonDefaultBlockAdminTest extends WebTestBase {
     $this->drupalLogin($admin_user);
     $new_theme = 'bartik';
     theme_enable(array($new_theme));
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . $new_theme);
+    $this->drupalGet('admin/structure/block/list/' . $new_theme);
     $this->assertText('Bartik(' . t('active tab') . ')', 'Tab for non-default theme found.');
   }
 }
diff --git a/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php b/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php
index 1303f4365b69..0ae93d41e500 100644
--- a/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php
+++ b/core/modules/menu/lib/Drupal/menu/Tests/MenuTest.php
@@ -161,7 +161,7 @@ class MenuTest extends MenuWebTestBase {
     // Enable the custom menu block.
     $menu_name = 'menu-' . $menu_name; // Drupal prepends the name with 'menu-'.
     // Confirm that the custom menu block is available.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add');
+    $this->drupalGet('admin/structure/block/list/' . config('system.theme')->get('default') . '/add');
     $this->assertText($label);
 
     // Enable the block.
@@ -379,7 +379,7 @@ class MenuTest extends MenuWebTestBase {
 
     // Make sure menu shows up with new name in block addition.
     $default_theme = variable_get('theme_default', 'stark');
-    $this->drupalget('admin/structure/block/list/block_plugin_ui:' . $default_theme . '/add');
+    $this->drupalget('admin/structure/block/list/' . $default_theme . '/add');
     $this->assertText($edit['label']);
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Access/SystemPluginUiCheck.php b/core/modules/system/lib/Drupal/system/Access/SystemPluginUiCheck.php
deleted file mode 100644
index db13644f9617..000000000000
--- a/core/modules/system/lib/Drupal/system/Access/SystemPluginUiCheck.php
+++ /dev/null
@@ -1,55 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\system\Access\SystemPluginUiCheck.
- */
-
-namespace Drupal\system\Access;
-
-use Drupal\Component\Plugin\PluginManagerInterface;
-use Drupal\Core\Access\AccessCheckInterface;
-use Symfony\Component\Routing\Route;
-use Symfony\Component\HttpFoundation\Request;
-
-/**
- * Access check for system routes.
- */
-class SystemPluginUiCheck implements AccessCheckInterface {
-
-  /**
-   * The plugin UI manager.
-   *
-   * @var \Drupal\Component\Plugin\PluginManagerInterface
-   */
-  protected $pluginUiManager;
-
-  /**
-   * Constructs a SystemController object.
-   *
-   * @param \Drupal\Component\Plugin\PluginManagerInterface $plugin_ui_manager
-   *   The plugin UI manager.
-   */
-  public function __construct(PluginManagerInterface $plugin_ui_manager) {
-    $this->pluginUiManager = $plugin_ui_manager;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function applies(Route $route) {
-    return array_key_exists('_access_system_plugin_ui', $route->getRequirements());
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function access(Route $route, Request $request) {
-    if ($request->attributes->get('plugin_id')) {
-      // Checks access for a given plugin using the plugin's access() method.
-      $plugin_ui = $this->pluginUiManager->createInstance($request->attributes->get('plugin_id'), array());
-      return $plugin_ui->access(NULL) ? static::ALLOW : static::DENY;
-    }
-  }
-
-}
diff --git a/core/modules/system/lib/Drupal/system/Controller/SystemController.php b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
deleted file mode 100644
index bd71353d88b8..000000000000
--- a/core/modules/system/lib/Drupal/system/Controller/SystemController.php
+++ /dev/null
@@ -1,56 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\system\Controller\SystemController.
- */
-
-namespace Drupal\system\Controller;
-
-use Drupal\Component\Utility\Tags;
-use Drupal\Component\Utility\Unicode;
-use Symfony\Component\DependencyInjection\ContainerAware;
-use Symfony\Component\HttpFoundation\JsonResponse;
-use Symfony\Component\HttpFoundation\Request;
-
-
-/**
- * Returns responses for System routes.
- */
-class SystemController extends ContainerAware {
-
-  /**
-   * Autocompletes any plugin system tied to a plugin UI plugin.
-   *
-   * The passed plugin_id indicates the specific plugin_ui plugin that is in use
-   * here. The documentation within the annotation of that plugin will contain a
-   * manager for the plugins that need to be autocompleted allowing this
-   * function to autocomplete plugins for any plugin type.
-   *
-   * @param string $plugin_id
-   *   The plugin id for the calling plugin.
-   * @param Request $request
-   *   The request object that contains the typed tags.
-   *
-   * @return \Symfony\Component\HttpFoundation\JsonResponse
-   *   The matched plugins as json.
-   */
-  public function autocomplete($plugin_id, Request $request) {
-    $string_typed = $request->query->get('q');
-    $string_typed = Tags::explode($string_typed);
-    $string = Unicode::strtolower(array_pop($string_typed));
-    $matches = array();
-    if ($string) {
-      $plugin_ui = $this->container->get('plugin.manager.system.plugin_ui')->getDefinition($plugin_id);
-      $manager = $this->container->get($plugin_ui['manager']);
-      $titles = array();
-      foreach($manager->getDefinitions() as $plugin_id => $plugin) {
-        $titles[$plugin_id] = $plugin[$plugin_ui['title_attribute']];
-      }
-      $matches = preg_grep("/\b". $string . "/i", $titles);
-    }
-
-    return new JsonResponse($matches);
-  }
-
-}
diff --git a/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php b/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php
deleted file mode 100644
index 9328a5c3394d..000000000000
--- a/core/modules/system/lib/Drupal/system/Plugin/Type/PluginUIManager.php
+++ /dev/null
@@ -1,51 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\system\Plugin\Type\PluginUIManager.
- */
-
-namespace Drupal\system\Plugin\Type;
-
-use Drupal\Component\Plugin\PluginManagerBase;
-use Drupal\Component\Plugin\Discovery\DerivativeDiscoveryDecorator;
-use Drupal\Core\Plugin\Discovery\AnnotatedClassDiscovery;
-use Drupal\Core\Plugin\Discovery\AlterDecorator;
-use Drupal\Core\Plugin\Discovery\CacheDecorator;
-use Drupal\Component\Plugin\Factory\DefaultFactory;
-
-/**
- * Manages discovery and instantiation of Plugin UI plugins.
- *
- * @todo This class needs @see references and/or more documentation.
- */
-class PluginUIManager extends PluginManagerBase {
-
-  /**
-   * Constructs a \Drupal\system\Plugin\Type\PluginUIManager object.
-   *
-   * @param \Traversable $namespaces
-   *   An object that implements \Traversable which contains the root paths
-   *   keyed by the corresponding namespace to look for plugin implementations,
-   */
-  public function __construct(\Traversable $namespaces) {
-    $this->discovery = new AnnotatedClassDiscovery('Plugin/PluginUI', $namespaces);
-    $this->discovery = new DerivativeDiscoveryDecorator($this->discovery);
-    $this->discovery = new AlterDecorator($this->discovery, 'plugin_ui');
-    $this->discovery = new CacheDecorator($this->discovery, 'plugin_ui');
-    $this->factory = new DefaultFactory($this->discovery);
-  }
-
-  /**
-   * Overrides \Drupal\Component\Plugin\PluginManagerBase::processDefinition().
-   */
-  public function processDefinition(&$definition, $plugin_id) {
-    $definition += array(
-      'default_task' => TRUE,
-      'task_title' => t('View'),
-      'task_suffix' => 'view',
-      'access_callback' => 'user_access',
-    );
-  }
-
-}
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index fc7bb6df23fe..1935f5c5c90d 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -964,83 +964,9 @@ function system_menu() {
     );
   }
 
-  foreach (drupal_container()->get('plugin.manager.system.plugin_ui')->getDefinitions() as $plugin_id => $plugin) {
-    if ($plugin['menu'] === TRUE) {
-      $items[$plugin['path'] . '/' . $plugin_id . '/' . $plugin['suffix']] = array(
-        'title' => $plugin['title'],
-        'page callback' => 'drupal_get_form',
-        'page arguments' => array($plugin['id'], $plugin_id),
-        'access callback' => 'system_plugin_ui_access',
-        'access arguments' => array($plugin_id),
-        'type' => $plugin['type'],
-      );
-      if (!empty($plugin['default_task'])) {
-        $items[$plugin['path'] . '/' . $plugin_id . '/' . $plugin['suffix'] . '/' . $plugin['task_suffix']] = array(
-          'title' => $plugin['task_title'],
-          'type' => MENU_DEFAULT_LOCAL_TASK,
-          'weight' => -10,
-        );
-      }
-      $items[$plugin['path'] . '/' . $plugin_id . '/%'] = array(
-        'title' => $plugin['title'],
-        'page callback' => 'drupal_get_form',
-        'page arguments' => array($plugin['id'], $plugin_id, (count(explode('/', $plugin['path'])) + 1)),
-        'access callback' => 'system_plugin_ui_access',
-        'access arguments' => array($plugin_id, (count(explode('/', $plugin['path'])) + 1)),
-        'type' => MENU_CALLBACK,
-      );
-      if (!empty($plugin['file'])) {
-        $items[$plugin['path'] . '/' . $plugin_id . '/' . $plugin['suffix']]['file'] = $plugin['file'];
-        $items[$plugin['path'] . '/' . $plugin_id . '/%']['file'] = $plugin['file'];
-        if (!empty($plugin['file_path'])) {
-          $items[$plugin['path'] . '/' . $plugin_id . '/' . $plugin['suffix']]['file path'] = $plugin['file_path'];
-          $items[$plugin['path'] . '/' . $plugin_id . '/%']['file path'] = $plugin['file_path'];
-        }
-      }
-    }
-  }
-
   return $items;
 }
 
-/**
- * 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);
-  $form = $plugin_ui->form($form, $form_state, $facet);
-  $form['#validate'][] = array($plugin_ui, 'formValidate');
-  $form['#submit'][] = array($plugin_ui, 'formSubmit');
-  return $form;
-}
-
-/**
- * Checks access for a given plugin using the plugin's access() method.
- *
- * @todo This needs more explanation, some @see, and parameter documentation.
- * @todo What the heck kind of parameter name is "facet"?
- */
-function system_plugin_ui_access($plugin, $facet = NULL) {
-  $plugin_ui = drupal_container()->get('plugin.manager.system.plugin_ui')->createInstance($plugin);
-  return $plugin_ui->access($facet);
-}
-
-/**
- * Implements hook_forms().
- */
-function system_forms() {
-  $forms = array();
-  foreach (drupal_container()->get('plugin.manager.system.plugin_ui')->getDefinitions() as $plugin_id => $plugin) {
-    if (empty($forms[$plugin['id']])) {
-      $forms[$plugin['id']]['callback'] = 'system_plugin_ui_form';
-    }
-  }
-  return $forms;
-}
-
 /**
  * Theme callback for the default batch page.
  */
diff --git a/core/modules/system/system.routing.yml b/core/modules/system/system.routing.yml
index 61363d6cda3e..017d4868c455 100644
--- a/core/modules/system/system.routing.yml
+++ b/core/modules/system/system.routing.yml
@@ -213,10 +213,3 @@ system_timezone:
     _controller: '\Drupal\system\Controller\TimezoneController::getTimezone'
   requirements:
     _access: 'TRUE'
-
-system_plugin_autocomplete:
-  pattern: '/system/autocomplete/{plugin_id}'
-  defaults:
-    _controller: 'Drupal\system\Controller\SystemController::autocomplete'
-  requirements:
-    _access_system_plugin_ui: 'TRUE'
diff --git a/core/modules/system/system.services.yml b/core/modules/system/system.services.yml
index 0c770d364b98..08d67adf70bd 100644
--- a/core/modules/system/system.services.yml
+++ b/core/modules/system/system.services.yml
@@ -3,14 +3,6 @@ services:
     class: Drupal\system\Access\CronAccessCheck
     tags:
       - { name: access_check }
-  access_check.system_plugin_ui:
-    class: Drupal\system\Access\SystemPluginUiCheck
-    tags:
-      - { name: access_check }
-    arguments: ['@plugin.manager.system.plugin_ui']
-  plugin.manager.system.plugin_ui:
-    class: Drupal\system\Plugin\Type\PluginUIManager
-    arguments: ['@container.namespaces']
   system.manager:
     class: Drupal\system\SystemManager
     arguments: ['@module_handler', '@database']
diff --git a/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php b/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php
index 0a8f18eba7cb..8f3f4eb26833 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Wizard/BasicTest.php
@@ -122,7 +122,7 @@ class BasicTest extends WizardTestBase {
     $this->assertLinkByHref(url($view3['page[path]']));
 
     // Confirm that the block is available in the block administration UI.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add');
+    $this->drupalGet('admin/structure/block/list/' . config('system.theme')->get('default') . '/add');
     $this->assertText('View: ' . $view3['label']);
 
     // Place the block.
diff --git a/core/modules/views/lib/Drupal/views/Tests/Wizard/ItemsPerPageTest.php b/core/modules/views/lib/Drupal/views/Tests/Wizard/ItemsPerPageTest.php
index e6808c74c505..485f048c1363 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Wizard/ItemsPerPageTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Wizard/ItemsPerPageTest.php
@@ -75,7 +75,7 @@ class ItemsPerPageTest extends WizardTestBase {
     $this->assertTrue($pos5 < $pos4 && $pos4 < $pos3 && $pos3 < $pos2, 'The nodes appear in the expected order in the page display.');
 
     // Confirm that the block is listed in the block administration UI.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add');
+    $this->drupalGet('admin/structure/block/list/' . config('system.theme')->get('default') . '/add');
     $this->assertText('View: ' . $view['label']);
 
     // Place the block, visit a page that displays the block, and check that the
diff --git a/core/modules/views_ui/lib/Drupal/views_ui/Tests/OverrideDisplaysTest.php b/core/modules/views_ui/lib/Drupal/views_ui/Tests/OverrideDisplaysTest.php
index 38b3d36b4b8a..1dab1f66a97b 100644
--- a/core/modules/views_ui/lib/Drupal/views_ui/Tests/OverrideDisplaysTest.php
+++ b/core/modules/views_ui/lib/Drupal/views_ui/Tests/OverrideDisplaysTest.php
@@ -54,7 +54,7 @@ class OverrideDisplaysTest extends UITestBase {
     $this->assertText($original_title);
 
     // Confirm that the view block is available in the block administration UI.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add');
+    $this->drupalGet('admin/structure/block/list/' . config('system.theme')->get('default') . '/add');
     $this->assertText('View: ' . $view['label']);
 
     // Place the block.
@@ -112,7 +112,7 @@ class OverrideDisplaysTest extends UITestBase {
     $this->assertNoText($view['block[title]']);
 
     // Confirm that the block is available in the block administration UI.
-    $this->drupalGet('admin/structure/block/list/block_plugin_ui:' . config('system.theme')->get('default') . '/add');
+    $this->drupalGet('admin/structure/block/list/' . config('system.theme')->get('default') . '/add');
     $this->assertText('View: ' . $view['label']);
 
     // Put the block into the first sidebar region, and make sure it will not