diff --git a/core/includes/batch.inc b/core/includes/batch.inc
index d12b603..94524e2 100644
--- a/core/includes/batch.inc
+++ b/core/includes/batch.inc
@@ -26,6 +26,8 @@
  *   The current request object.
  *
  * @see _batch_shutdown()
+ *
+ * @internal
  */
 function _batch_page(Request $request) {
   $batch = &batch_get();
@@ -111,6 +113,8 @@ function _batch_page(Request $request) {
  *
  * @return bool
  *   TRUE if the batch information needs to be updated; FALSE otherwise.
+ *
+ * @internal
  */
 function _batch_needs_update($new_value = NULL) {
   $needs_update = &drupal_static(__FUNCTION__, FALSE);
@@ -127,18 +131,27 @@ function _batch_needs_update($new_value = NULL) {
  *
  * @see _batch_progress_page_js()
  * @see _batch_process()
+ *
+ * @internal
  */
 function _batch_do() {
   // Perform actual processing.
   list($percentage, $message, $label) = _batch_process();
 
-  return new JsonResponse(['status' => TRUE, 'percentage' => $percentage, 'message' => $message, 'label' => $label]);
+  return new JsonResponse([
+    'status' => TRUE,
+    'percentage' => $percentage,
+    'message' => $message,
+    'label' => $label,
+  ]);
 }
 
 /**
  * Outputs a batch processing page.
  *
  * @see _batch_process()
+ *
+ * @internal
  */
 function _batch_progress_page() {
   $batch = &batch_get();
@@ -217,7 +230,8 @@ function _batch_progress_page() {
           'batch_progress_meta_refresh',
         ],
       ],
-      // Adds JavaScript code and settings for clients where JavaScript is enabled.
+      // Adds JavaScript code and settings for clients where JavaScript is
+      // enabled.
       'drupalSettings' => [
         'batch' => [
           'errorMessage' => $current_set['error_message'] . '<br />' . $batch['error_message'],
@@ -243,6 +257,8 @@ function _batch_progress_page() {
  *
  * @return array
  *   An array containing a completion value (in percent) and a status message.
+ *
+ * @internal
  */
 function _batch_process() {
   return BatchQueueController::processQueue();
@@ -250,6 +266,8 @@ function _batch_process() {
 
 /**
  * Returns the batch set being currently processed.
+ *
+ * @internal
  */
 function &_batch_current_set() {
   return BatchQueueController::getCurrentSet();
@@ -265,6 +283,8 @@ function &_batch_current_set() {
  * @return true|null
  *   TRUE if a subsequent set was found in the batch; no value will be returned
  *   if no subsequent set was found.
+ *
+ * @internal
  */
 function _batch_next_set() {
   return BatchQueueController::nextSet();
@@ -275,6 +295,8 @@ function _batch_next_set() {
  *
  * Call the 'finished' callback of each batch set to allow custom handling of
  * the results and resolve page redirection.
+ *
+ * @internal
  */
 function _batch_finished() {
   return BatchQueueController::finishedProcessing();
@@ -285,6 +307,8 @@ function _batch_finished() {
  *
  * @see _batch_page()
  * @see drupal_register_shutdown_function()
+ *
+ * @internal
  */
 function _batch_shutdown() {
   if (($batch = batch_get()) && _batch_needs_update()) {
diff --git a/core/includes/form.inc b/core/includes/form.inc
index b4a8e10..585dbae 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -713,9 +713,6 @@ function template_preprocess_form_element_label(&$variables) {
  *       Typically, the class will either be \Drupal\Core\Queue\Batch or
  *       \Drupal\Core\Queue\BatchMemory. Defaults to Batch if progressive is
  *       TRUE, or to BatchMemory if progressive is FALSE.
- *
- * @deprecated as of Drupal 8.2.x, will be removed in Drupal 9.0.0. Create a
- *   \Drupal\Core\Batch\Batch object and use the enqueue() function.
  */
 function batch_set($batch_definition) {
   if (!($batch_definition instanceof Batch)) {
@@ -746,16 +743,12 @@ function batch_set($batch_definition) {
  * @param \Drupal\Core\Url $url
  *   (optional) URL of the batch processing page. Should only be used for
  *   separate scripts like update.php.
- * @param $redirect_callback
+ * @param string|null $redirect_callback
  *   (optional) Specify a function to be called to redirect to the progressive
  *   processing page.
  *
  * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
  *   A redirect response if the batch is progressive. No return value otherwise.
- *
- * @deprecated as of Drupal 8.2.x, will be removed in Drupal 9.0.0. Use
- *   \Drupal\Core\Batch\Batch::process() instead or the process() function on
- *   an existing Batch object.
  */
 function batch_process($redirect = NULL, Url $url = NULL, $redirect_callback = NULL) {
   return BatchQueueController::process($redirect, $url, $redirect_callback);
diff --git a/core/lib/Drupal/Core/Batch/Batch.php b/core/lib/Drupal/Core/Batch/Batch.php
index 5475d06..291b785 100644
--- a/core/lib/Drupal/Core/Batch/Batch.php
+++ b/core/lib/Drupal/Core/Batch/Batch.php
@@ -137,7 +137,7 @@ public static function create() {
    *   A new object.
    */
   public static function createFromTitle($title) {
-    return self::create()->setTitle($title);
+    return static::create()->setTitle($title);
   }
 
   /**
@@ -150,7 +150,7 @@ public static function createFromTitle($title) {
    *   A new initialized object.
    */
   public static function createFromArray(array $batch_definition) {
-    $new_batch = self::create();
+    $new_batch = static::create();
 
     if (isset($batch_definition['operations'])) {
       foreach ($batch_definition['operations'] as list($callback, $arguments)) {
@@ -199,16 +199,14 @@ public static function createFromArray(array $batch_definition) {
       $new_batch->setProgressive($batch_definition['progressive']);
     }
 
-    if (isset($batch_definition['queue'])) {
-      if (
-        isset($batch_definition['queue']['name']) &&
-        isset($batch_definition['queue']['class'])
-      ) {
-        $new_batch->setQueue(
-          $batch_definition['queue']['name'],
-          $batch_definition['queue']['class']
-        );
-      }
+    if (
+      isset($batch_definition['queue']['name']) &&
+      isset($batch_definition['queue']['class'])
+    ) {
+      $new_batch->setQueue(
+        $batch_definition['queue']['name'],
+        $batch_definition['queue']['class']
+      );
     }
 
     return $new_batch;
diff --git a/core/lib/Drupal/Core/Batch/BatchQueueController.php b/core/lib/Drupal/Core/Batch/BatchQueueController.php
index 408dd90..c96c713 100644
--- a/core/lib/Drupal/Core/Batch/BatchQueueController.php
+++ b/core/lib/Drupal/Core/Batch/BatchQueueController.php
@@ -14,6 +14,8 @@
 
 /**
  * Handles operations on the batch processes to be handled.
+ *
+ * @internal
  */
 class BatchQueueController {