diff --git a/core/modules/serialization/lib/Drupal/serialization/RegisterSerializationClassesPass.php b/core/modules/serialization/lib/Drupal/serialization/RegisterSerializationClassesPass.php
index 15b1e1b..b7ad9d8 100644
--- a/core/modules/serialization/lib/Drupal/serialization/RegisterSerializationClassesPass.php
+++ b/core/modules/serialization/lib/Drupal/serialization/RegisterSerializationClassesPass.php
@@ -12,12 +12,12 @@
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
 
 /**
- * Adds servies tagged 'nested_matcher' services to the tagged_matcher service.
+ * Adds services tagged 'normalizer' and 'encoder' to the Serializer.
  */
 class RegisterSerializationClassesPass implements CompilerPassInterface {
 
   /**
-   * Adds services tagged with normalizer or encoder to the Serializer.
+   * Adds services to the Serializer.
    *
    * @param \Symfony\Component\DependencyInjection\ContainerBuilder $container
    *   The container to process.
@@ -49,17 +49,18 @@ public function process(ContainerBuilder $container) {
    *
    * The highest priority number is the highest priority (reverse sorting).
    *
-   * @param array $array
+   * @param array $services
    *   A nested array of Normalizers/Encoders.
    *
    * @return array
    *   An array of Normalizers/Encoders to be used by Serializer.
    */
-  protected function sort($array) {
+  protected function sort($services) {
     $sorted = array();
-    krsort($array);
+    krsort($services);
 
-    foreach ($array as $a) {
+    // Flatten the array.
+    foreach ($services as $a) {
       $sorted = array_merge($sorted, $a);
     }
 
diff --git a/core/modules/serialization/lib/Drupal/serialization/SerializationBundle.php b/core/modules/serialization/lib/Drupal/serialization/SerializationBundle.php
index 346ac95..4ccab45 100644
--- a/core/modules/serialization/lib/Drupal/serialization/SerializationBundle.php
+++ b/core/modules/serialization/lib/Drupal/serialization/SerializationBundle.php
@@ -20,6 +20,8 @@ class SerializationBundle extends Bundle {
    * Overrides Symfony\Component\HttpKernel\Bundle\Bundle::build().
    */
   public function build(ContainerBuilder $container) {
+    // Add Serializer with empty array arguments, which will be replaced in the
+    // compiler pass.
     $container->register('serializer', 'Symfony\Component\Serializer\Serializer')
       ->addArgument(array())
       ->addArgument(array());
diff --git a/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestEncoder.php b/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestEncoder.php
index a367c65..097bec0 100644
--- a/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestEncoder.php
+++ b/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestEncoder.php
@@ -10,6 +10,7 @@
 use Symfony\Component\Serializer\Encoder\EncoderInterface;
 
 class SerializationTestEncoder implements EncoderInterface {
+
   /**
    * The format that this Encoder supports.
    *
@@ -21,9 +22,9 @@ class SerializationTestEncoder implements EncoderInterface {
    * Implementation required. This function not used for testing.
    *
    * @param mixed $data
-   *   Data to encode
+   *   Data to encode.
    * @param string $format
-   *   Format name
+   *   Format name.
    */
   public function encode($data, $format) {
   }
diff --git a/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestNormalizer.php b/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestNormalizer.php
index 8000d40..01f31bc 100644
--- a/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestNormalizer.php
+++ b/core/modules/serialization/tests/modules/serilization_test/lib/Drupal/serialization_test/SerializationTestNormalizer.php
@@ -10,6 +10,7 @@
 use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
 
 class SerializationTestNormalizer implements NormalizerInterface {
+
   /**
    * The format that this Normalizer supports.
    *
@@ -33,7 +34,7 @@ public function normalize($object, $format = NULL) {
   }
 
   /**
-   * Checks whether the data and format are supported by this normalizer.
+   * Checks whether format is supported by this normalizer.
    *
    * @param mixed  $data
    *   Data to normalize.
@@ -44,7 +45,6 @@ public function normalize($object, $format = NULL) {
    *   Returns TRUE if the normalizer can handle the request.
    */
   public function supportsNormalization($data, $format = NULL) {
-    // If this is an Entity object and the request is for JSON-LD.
     return static::$format === $format;
   }
 }