diff --git a/core/modules/datetime/lib/Drupal/datetime/Plugin/field/formatter/DatetimeDefaultFormatter.php b/core/modules/datetime/lib/Drupal/datetime/Plugin/field/formatter/DatetimeDefaultFormatter.php
index 2ed1b8a..88a2184 100644
--- a/core/modules/datetime/lib/Drupal/datetime/Plugin/field/formatter/DatetimeDefaultFormatter.php
+++ b/core/modules/datetime/lib/Drupal/datetime/Plugin/field/formatter/DatetimeDefaultFormatter.php
@@ -64,15 +64,15 @@ class DateTimeDefaultFormatter extends FormatterBase implements ContainerFactory
    *   The formatter label display setting.
    * @param string $view_mode
    *   The view mode.
-   * @param \Drupal\Core\Datetime\Date $dateService
+   * @param \Drupal\Core\Datetime\Date $date_service
    *   The date service.
    * @param \Drupal\Core\Entity\EntityStorageControllerInterface $date_storage
    *   The date storage controller.
    */
-  public function __construct($plugin_id, array $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, Date $dateService, EntityStorageControllerInterface $date_storage) {
+  public function __construct($plugin_id, array $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $view_mode, Date $date_service, EntityStorageControllerInterface $date_storage) {
     parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $view_mode);
 
-    $this->dateService = $dateService;
+    $this->dateService = $date_service;
     $this->dateStorage = $date_storage;
   }
 
diff --git a/core/modules/system/config/system.date_format.fallback.yml b/core/modules/system/config/system.date_format.fallback.yml
index e8cab2f..a9e3eb1 100644
--- a/core/modules/system/config/system.date_format.fallback.yml
+++ b/core/modules/system/config/system.date_format.fallback.yml
@@ -1,6 +1,6 @@
 id: fallback
 uuid: cf0ad071-ded7-4750-b008-8c74f200ff8d
-label: 'Fallback date'
+label: 'Fallback date format'
 status: '1'
 langcode: en
 locked: '1'
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/FormatDateTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/FormatDateTest.php
index 84779f5..6c0d23a 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/FormatDateTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/FormatDateTest.php
@@ -83,7 +83,7 @@ function testAdminDefinedFormatDate() {
     $timestamp = strtotime('2007-03-10T00:00:00+00:00');
     $this->assertIdentical(format_date($timestamp, 'example_style', '', 'America/Los_Angeles'), '9 Mar 07', 'Test format_date() using an admin-defined date type.');
     $this->assertIdentical(format_date($timestamp, 'example_style_uppercase', '', 'America/Los_Angeles'), '9 Mar 2007', 'Test format_date() using an admin-defined date type with different case.');
-    $this->assertIdentical(format_date($timestamp, 'undefined_style'), format_date($timestamp, 'fallback'), 'Test format_date() defaulting to medium when $type not found.');
+    $this->assertIdentical(format_date($timestamp, 'undefined_style'), format_date($timestamp, 'fallback'), 'Test format_date() defaulting to `fallback` when $type not found.');
   }
 
   /**