diff --git a/core/core.services.yml b/core/core.services.yml
index 0f21eb8..296e241 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -482,6 +482,7 @@ services:
   entity.manager:
     class: Drupal\Core\Entity\EntityManager
     arguments: ['@entity_type.manager', '@entity_type.repository', '@entity_type.bundle.manager', '@entity_display.manager', '@entity_field.manager', '@entity_type.listener', '@entity_definition.repository', '@entity.repository', '@entity_bundle.listener', '@field_storage_definition.listener', '@field_definition.listener']
+    # @todo Remove this tag in https://www.drupal.org/node/2549143.
     tags:
       - { name: plugin_manager_cache_clear }
   entity_type.manager:
diff --git a/core/lib/Drupal/Core/Entity/EntityBundleListener.php b/core/lib/Drupal/Core/Entity/EntityBundleListener.php
index f837655..a3e036b 100644
--- a/core/lib/Drupal/Core/Entity/EntityBundleListener.php
+++ b/core/lib/Drupal/Core/Entity/EntityBundleListener.php
@@ -10,7 +10,7 @@
 use Drupal\Core\Extension\ModuleHandlerInterface;
 
 /**
- * @todo.
+ * Reacts to entity bundle CRUD on behalf of the Entity system.
  */
 class EntityBundleListener implements EntityBundleListenerInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityDisplayManager.php b/core/lib/Drupal/Core/Entity/EntityDisplayManager.php
index 4fbf562..6a310cf 100644
--- a/core/lib/Drupal/Core/Entity/EntityDisplayManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityDisplayManager.php
@@ -15,7 +15,7 @@
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 
 /**
- * @todo.
+ * Manages the discovery of entity display objects (view modes and form modes).
  */
 class EntityDisplayManager implements EntityDisplayManagerInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityFieldManager.php b/core/lib/Drupal/Core/Entity/EntityFieldManager.php
index 9dd582c..94d2873 100644
--- a/core/lib/Drupal/Core/Entity/EntityFieldManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityFieldManager.php
@@ -18,7 +18,10 @@
 use Drupal\Core\TypedData\TypedDataManager;
 
 /**
- * @todo.
+ * Manages the discovery of entity fields.
+ *
+ * This includes field definitions, base field definitions, and field storage
+ * definitions)
  */
 class EntityFieldManager implements EntityFieldManagerInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityManager.php b/core/lib/Drupal/Core/Entity/EntityManager.php
index 2a06574..8dd88cc 100644
--- a/core/lib/Drupal/Core/Entity/EntityManager.php
+++ b/core/lib/Drupal/Core/Entity/EntityManager.php
@@ -144,7 +144,8 @@ public function clearCachedDefinitions() {
     $this->entityTypeManager->clearCachedDefinitions();
 
     // @todo None of these are plugin managers, and they should not co-opt
-    //   this method for managing its caches.
+    //   this method for managing its caches. Remove in
+    //   https://www.drupal.org/node/2549143.
     $this->entityTypeBundleManager->clearCachedBundles();
     $this->entityFieldManager->clearCachedFieldDefinitions();
     $this->entityTypeRepository->clearCachedDefinitions();
diff --git a/core/lib/Drupal/Core/Entity/EntityRepository.php b/core/lib/Drupal/Core/Entity/EntityRepository.php
index b99b2ad..58381d1 100644
--- a/core/lib/Drupal/Core/Entity/EntityRepository.php
+++ b/core/lib/Drupal/Core/Entity/EntityRepository.php
@@ -13,7 +13,7 @@
 use Drupal\Core\TypedData\TranslatableInterface;
 
 /**
- * @todo.
+ * Provides several mechanisms for retrieving entities.
  */
 class EntityRepository implements EntityRepositoryInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityRepositoryInterface.php b/core/lib/Drupal/Core/Entity/EntityRepositoryInterface.php
index c37be4a..0946ee9 100644
--- a/core/lib/Drupal/Core/Entity/EntityRepositoryInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityRepositoryInterface.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\Entity;
 
 /**
- * @todo.
+ * Provides an interface for an entity repository.
  */
 interface EntityRepositoryInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityTypeListener.php b/core/lib/Drupal/Core/Entity/EntityTypeListener.php
index 918e438..e7f0546 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeListener.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeListener.php
@@ -10,7 +10,7 @@
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 /**
- * @todo.
+ * Reacts to entity type CRUD on behalf of the Entity system.
  */
 class EntityTypeListener implements EntityTypeListenerInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php b/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php
index a3cfeb0..0f23f62 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeRepositoryInterface.php
@@ -51,6 +51,8 @@ public function getEntityTypeFromClass($class_name);
    * Clear the static cache.
    *
    * @deprecated
+   *
+   * @todo Remove in https://www.drupal.org/node/2549143.
    */
   public function clearCachedDefinitions();
 
diff --git a/core/lib/Drupal/Core/Field/FieldDefinitionListener.php b/core/lib/Drupal/Core/Field/FieldDefinitionListener.php
index ea6eebf..bd303ad 100644
--- a/core/lib/Drupal/Core/Field/FieldDefinitionListener.php
+++ b/core/lib/Drupal/Core/Field/FieldDefinitionListener.php
@@ -13,7 +13,7 @@
 use Drupal\Core\KeyValueStore\KeyValueFactoryInterface;
 
 /**
- * @todo.
+ * Reacts to field definition CRUD on behalf of the Entity system.
  */
 class FieldDefinitionListener implements FieldDefinitionListenerInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FieldStorageDefinitionListener.php b/core/lib/Drupal/Core/Field/FieldStorageDefinitionListener.php
index 9070b12..e0dafe5 100644
--- a/core/lib/Drupal/Core/Field/FieldStorageDefinitionListener.php
+++ b/core/lib/Drupal/Core/Field/FieldStorageDefinitionListener.php
@@ -13,7 +13,7 @@
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 /**
- * @todo.
+ * Reacts to field storage definition CRUD on behalf of the Entity system.
  */
 class FieldStorageDefinitionListener implements FieldStorageDefinitionListenerInterface {