diff --git a/core/modules/migrate_drupal/src/Plugin/migrate/builder/d6/CckMigration.php b/core/modules/migrate_drupal/src/Plugin/migrate/builder/d6/CckMigration.php
deleted file mode 100644
index eba6dbb..0000000
--- a/core/modules/migrate_drupal/src/Plugin/migrate/builder/d6/CckMigration.php
+++ /dev/null
@@ -1,67 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\migrate_drupal\Plugin\migrate\builder\d6\CckMigration.
- */
-
-namespace Drupal\migrate_drupal\Plugin\migrate\builder\d6;
-
-use Drupal\migrate\Exception\RequirementsException;
-use Drupal\migrate\Plugin\RequirementsInterface;
-use Drupal\migrate_drupal\Plugin\migrate\builder\CckBuilder;
-
-/**
- * @PluginID("d6_cck_migration")
- */
-class CckMigration extends CckBuilder {
-
-  /**
-   * List of cckfield plugin IDs which have already run.
-   *
-   * @var string[]
-   */
-  protected $processedFieldTypes = [];
-
-  /**
-   * {@inheritdoc}
-   */
-  public function buildMigrations(array $template) {
-    $migration = Migration::create($template);
-
-    $source_plugin = $migration->getSourcePlugin();
-    // The source plugin will throw RequirementsException if CCK is not enabled,
-    // in which case there is nothing else for us to do.
-    if ($source_plugin instanceof RequirementsInterface) {
-      try {
-        $source_plugin->checkRequirements();
-      }
-      catch (RequirementsException $e) {
-        return [$migration];
-      }
-    }
-
-    // Loop through every field that will be migrated.
-    foreach ($source_plugin as $field) {
-      $field_type = $field->getSourceProperty('type');
-
-      // Each field type should only be processed once.
-      if (in_array($field_type, $this->processedFieldTypes)) {
-        continue;
-      }
-      // Only process the current field type if a relevant cckfield plugin
-      // exists.
-      elseif ($this->cckPluginManager->hasDefinition($field_type)) {
-        $this->processedFieldTypes[] = $field_type;
-        // Allow the cckfield plugin to alter the migration as necessary so that
-        // it knows how to handle fields of this type.
-        $this->cckPluginManager
-          ->createInstance($field_type, [], $migration)
-          ->{$this->configuration['cck_plugin_method']}($migration);
-      }
-    }
-
-    return [$migration];
-  }
-
-}
diff --git a/core/modules/node/src/Plugin/migrate/builder/d6/Node.php b/core/modules/node/src/Plugin/migrate/builder/d6/Node.php
deleted file mode 100644
index 5e57456..0000000
--- a/core/modules/node/src/Plugin/migrate/builder/d6/Node.php
+++ /dev/null
@@ -1,74 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\node\Plugin\migrate\builder\d6\Node.
- */
-
-namespace Drupal\node\Plugin\migrate\builder\d6;
-
-use Drupal\migrate\Exception\RequirementsException;
-use Drupal\migrate_drupal\Plugin\migrate\builder\CckBuilder;
-
-/**
- * @PluginID("d6_node")
- */
-class Node extends CckBuilder {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function buildMigrations(array $template) {
-    $migrations = [];
-
-    // Read all CCK field instance definitions in the source database.
-    $fields = array();
-    $source_plugin = $this->getSourcePlugin('d6_field_instance', $template['source']);
-    try {
-      $source_plugin->checkRequirements();
-
-      foreach ($source_plugin as $field) {
-        $info = $field->getSource();
-        $fields[$info['type_name']][$info['field_name']] = $info;
-      }
-    }
-    catch (RequirementsException $e) {
-      // Don't do anything; $fields will be empty.
-    }
-
-    foreach ($this->getSourcePlugin('d6_node_type', $template['source']) as $row) {
-      $node_type = $row->getSourceProperty('type');
-      $values = $template;
-      $values['id'] = $template['id'] . '__' . $node_type;
-
-      $label = $template['label'];
-      $values['label'] = $this->t("@label (@type)", ['@label' => $label, '@type' => $node_type]);
-      $values['source']['node_type'] = $node_type;
-
-      // If this migration is based on the d6_node_revision template, it should
-      // explicitly depend on the corresponding d6_node variant.
-      if ($template['id'] == 'd6_node_revision') {
-        $values['migration_dependencies']['required'][] = 'd6_node__' . $node_type;
-      }
-
-      $migration = Migration::create($values);
-
-      if (isset($fields[$node_type])) {
-        foreach ($fields[$node_type] as $field => $info) {
-          if ($this->cckPluginManager->hasDefinition($info['type'])) {
-            $this->getCckPlugin($info['type'])
-              ->processCckFieldValues($migration, $field, $info);
-          }
-          else {
-            $migration->setProcessOfProperty($field, $field);
-          }
-        }
-      }
-
-      $migrations[] = $migration;
-    }
-
-    return $migrations;
-  }
-
-}
diff --git a/core/modules/node/src/Tests/Migrate/d7/NodeMigrateDeriverTest.php b/core/modules/node/src/Tests/Migrate/d7/NodeMigrateDeriverTest.php
index 27da131..9a05cac 100644
--- a/core/modules/node/src/Tests/Migrate/d7/NodeMigrateDeriverTest.php
+++ b/core/modules/node/src/Tests/Migrate/d7/NodeMigrateDeriverTest.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\node\Tests\Migrate\d7\NodeBuilderTest.
+ * Contains \Drupal\node\Tests\Migrate\d7\NodeMigrateDeriverTest.
  */
 
 namespace Drupal\node\Tests\Migrate\d7;
diff --git a/core/modules/user/src/Plugin/migrate/User.php b/core/modules/user/src/Plugin/migrate/User.php
index a828299..adf6088 100644
--- a/core/modules/user/src/Plugin/migrate/User.php
+++ b/core/modules/user/src/Plugin/migrate/User.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\user\Plugin\migrate\builder\d7\User.
+ * Contains \Drupal\user\Plugin\migrate\User.
  */
 
 namespace Drupal\user\Plugin\migrate;