diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 8128ce5..febb1bf 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -326,6 +326,7 @@ function _block_get_renderable_region($list = array()) {
     else {
       $key_components = explode('.', $key);
       $id = array_pop($key_components);
+      // @todo http://drupal.org/node/1942286
       $build[$key] = array(
         '#entity' => $block,
         '#block' => (object) $block->getPlugin()->getConfig(),
@@ -536,6 +537,7 @@ function block_rebuild() {
 function template_preprocess_block(&$variables) {
   $block_counter = &drupal_static(__FUNCTION__, array());
 
+  // @todo http://drupal.org/node/1942286
   $variables['block'] = (object) $variables['elements']['#block'];
 
   // All blocks get an independent counter for each region.
diff --git a/core/modules/block/lib/Drupal/block/BlockBase.php b/core/modules/block/lib/Drupal/block/BlockBase.php
index 7351e00..9f83308 100644
--- a/core/modules/block/lib/Drupal/block/BlockBase.php
+++ b/core/modules/block/lib/Drupal/block/BlockBase.php
@@ -479,19 +479,15 @@ public function build() {
     $build = array();
     $content = array();
     if ($content = $this->blockBuild()) {
+      // @todo http://drupal.org/node/1942286
       $build = array(
         '#block' => (object) $this->getConfig(),
         '#theme_wrappers' => array('block'),
-        '#block_config' => array(
-          'id' => $this->configuration['plugin'],
-          'region' => $this->configuration['region'],
-          'module' => $this->configuration['module'],
-          'label' => check_plain($this->configuration['label']),
-        ),
       );
       // The label is the only string we actually render, so we need to handle
       // it specially.
-      // @Todo: Give the implications of this line further thought in #1941244.
+      // @todo: Give the implications of this line further thought in
+      // http://drupal.org/node/1941244.
       $build['#block']->label = check_plain($this->configuration['label']);
     }
     $build['content'] = $content;
@@ -510,6 +506,6 @@ public function build() {
    *
    * @see \Drupal\block\BlockRenderController
    */
-  abstract public function blockBuild();
+  abstract protected function blockBuild();
 
 }
diff --git a/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php b/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
index 15ce633..009c1a6 100644
--- a/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
+++ b/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
@@ -200,6 +200,10 @@ public function get($property_name, $langcode = NULL) {
    * the entity within the settings property. Setting of the settings property
    * directly is supported, but all set() calls to the settings property are
    * additive and will not remove settings values.
+   *
+   * @todo The basic functionality of this cannot change. The plugin
+   * configuration and entity values must always be up to date, but we should
+   * revisit whether this can be simplified. http://drupal.org/node/1942262
    */
   public function set($property_name, $value) {
     if (!in_array($property_name, $this->exportProperties()) && $property_name != 'settings') {
@@ -267,6 +271,8 @@ public function getExportProperties() {
    * Implements \Drupal\Core\Entity\EntityInterface::save().
    */
   public function save() {
+    // Get any key value pairs in the plugin configuration that are not in the
+    // entity's properties and add them to the entity's settings property.
     $this->settings = array_diff_key($this->getPlugin()->getConfig(), $this->getExportProperties());
     return parent::save();
   }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
index b11363d..10ad233 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
@@ -44,6 +44,7 @@ function testBlockThemeHookSuggestions() {
     ));
 
     $variables = array();
+    // @todo http://drupal.org/node/1942286
     $variables['elements']['#block'] = (object) $block->getPlugin()->getConfig();
     $variables['elements']['#children'] = '';
     // Test adding a class to the block content.