diff --git a/core/modules/filter/lib/Drupal/filter/FilterBag.php b/core/modules/filter/lib/Drupal/filter/FilterBag.php
index 4771691..0d521c6 100644
--- a/core/modules/filter/lib/Drupal/filter/FilterBag.php
+++ b/core/modules/filter/lib/Drupal/filter/FilterBag.php
@@ -7,10 +7,8 @@
 
 namespace Drupal\filter;
 
-use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Component\Plugin\DefaultPluginBag;
-use Drupal\Component\Utility\String;
 
 /**
  * A collection of filters.
diff --git a/core/modules/filter/lib/Drupal/filter/FilterPluginManager.php b/core/modules/filter/lib/Drupal/filter/FilterPluginManager.php
index 4cf3df0..0189bc5 100644
--- a/core/modules/filter/lib/Drupal/filter/FilterPluginManager.php
+++ b/core/modules/filter/lib/Drupal/filter/FilterPluginManager.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\filter;
 
-use Drupal\Component\Plugin\Exception\PluginException;
 use Drupal\Component\Plugin\PluginManagerBase;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\Language\Language;
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilterFormatUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilterFormatUpgradePathTest.php
index 12561d7..c48cc72 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilterFormatUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/FilterFormatUpgradePathTest.php
@@ -74,7 +74,7 @@ public function testFilterFormatUpgrade() {
     $this->assertNoFieldChecked('edit-5-use-text-format-format-one', 'Use text format format_one permission for role is set correctly.');
     $this->assertNoFieldChecked('edit-5-use-text-format-format-two', 'Use text format format_two permission for role is set correctly.');
 
-    // Check that missing
+    // Check that the format has the missing filter.
     $two = filter_format_load('format_two');
     $this->assertTrue($two->filters()->has('missing_filter'));
 
@@ -90,7 +90,6 @@ public function testFilterFormatUpgrade() {
     filter_formats_reset();
     $two = filter_format_load('format_two');
     $this->assertFalse($two->filters()->has('missing_filter'));
-
   }
 
 }