diff -u b/core/modules/file/migration_templates/d7_file.yml b/core/modules/file/migration_templates/d7_file.yml
--- b/core/modules/file/migration_templates/d7_file.yml
+++ b/core/modules/file/migration_templates/d7_file.yml
@@ -1,7 +1,7 @@
 # Every migration that references a file by Drupal 7 fid should specify this
 # migration as an optional dependency.
 id: d7_file
-label: Public Files
+label: Files
 audit: true
 migration_tags:
   - Drupal 7
diff -u b/core/modules/file/migration_templates/d7_file_private.yml b/core/modules/file/migration_templates/d7_file_private.yml
--- b/core/modules/file/migration_templates/d7_file_private.yml
+++ b/core/modules/file/migration_templates/d7_file_private.yml
@@ -1,5 +1,5 @@
 id: d7_file_private
-label: Private Files
+label: Files
 audit: true
 migration_tags:
   - Drupal 7
diff -u b/core/modules/migrate/src/Audit/AuditException.php b/core/modules/migrate/src/Audit/AuditException.php
--- b/core/modules/migrate/src/Audit/AuditException.php
+++ b/core/modules/migrate/src/Audit/AuditException.php
@@ -20,7 +20,7 @@
    *   (optional) The previous exception.
    */
   public function __construct(MigrationInterface $migration, $message, \Exception $previous = NULL) {
-    $message = 'Cannot audit migration ' . $migration->id() . ': ' . $message;
+    $message = sprintf('Cannot audit migration %s: %s', $migration->id(), $message);
     parent::__construct($message, 0, $previous);
   }
 
diff -u b/core/modules/migrate/src/Audit/IdAuditor.php b/core/modules/migrate/src/Audit/IdAuditor.php
--- b/core/modules/migrate/src/Audit/IdAuditor.php
+++ b/core/modules/migrate/src/Audit/IdAuditor.php
@@ -20,14 +20,16 @@
       return [];
     }
 
+    $interface = MaximumValueInterface::class;
+
     $destination = $migration->getDestinationPlugin();
     if (!$destination instanceof MaximumValueInterface) {
-      throw new AuditException($migration, 'Destination plugin does not implement ' . MaximumValueInterface::class);
+      throw new AuditException($migration, "Destination does not implement $interface");
     }
 
     $id_map = $migration->getIdMap();
     if (!$id_map instanceof MaximumValueInterface) {
-      throw new AuditException($migration, 'ID map plugin does not implement ' . MaximumValueInterface::class);
+      throw new AuditException($migration, "ID map does not implement $interface");
     }
 
     if ($destination->max() > $id_map->max()) {
diff -u b/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php b/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
--- b/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
+++ b/core/modules/migrate/src/Plugin/migrate/id_map/Sql.php
@@ -13,7 +13,6 @@
 use Drupal\migrate\MigrateException;
 use Drupal\migrate\MigrateMessageInterface;
 use Drupal\migrate\Plugin\MigrateIdMapInterface;
-use Drupal\migrate\Plugin\MigrationPluginManagerInterface;
 use Drupal\migrate\Row;
 use Drupal\migrate\Event\MigrateEvents;
 use Drupal\migrate\Event\MigrateMapSaveEvent;
@@ -44,13 +43,6 @@
   protected $eventDispatcher;
 
   /**
-   * The migration plugin manager.
-   *
-   * @var \Drupal\migrate\Plugin\MigrationPluginManagerInterface
-   */
-  protected $migrationPluginManager;
-
-  /**
    * The migration map table name.
    *
    * @var string
@@ -163,14 +155,11 @@
    *   The migration to do.
    * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
    *   The event dispatcher.
-   * @param \Drupal\migrate\Plugin\MigrationPluginManagerInterface $migration_plugin_manager
-   *   The migration plugin manager.
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EventDispatcherInterface $event_dispatcher, MigrationPluginManagerInterface $migration_plugin_manager) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EventDispatcherInterface $event_dispatcher) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->migration = $migration;
     $this->eventDispatcher = $event_dispatcher;
-    $this->migrationPluginManager = $migration_plugin_manager;
     $this->message = new MigrateMessage();
   }
 
@@ -951,7 +940,7 @@
       }
     );
     if (empty($destination_ids)) {
-      throw new \LogicException('TODO');
+      throw new \LogicException('Cannot determine the highest migrated ID without an integer ID column');
     }
     $field_name = key($destination_ids);
 
@@ -966,12 +955,16 @@
     // If there's a bundle, it means we have a derived migration and we need to
     // find all the mapping tables from the related derived migrations.
     if ($base_id = substr($migration_id, 0, strpos($migration_id, ':'))) {
-      $migrations = $this->migrationPluginManager->getDefinitions();
+      // @TODO Inject the plugin manager as a dependency.
+      /** @var \Drupal\migrate\Plugin\MigrationPluginManagerInterface $migration_manager */
+      $migration_manager = \Drupal::service('plugin.manager.migration');
+
+      $migrations = $migration_manager->getDefinitions();
       foreach ($migrations as $migration_id => $migration) {
         if ($migration['id'] == $base_id) {
           // Get this derived migration's mapping table and add it to the list
           // of mapping tables to look in for the highest ID.
-          $stub = $this->migrationPluginManager->createInstance($migration_id);
+          $stub = $migration_manager->createInstance($migration_id);
           $map_tables[$migration_id] = $stub->getIdMap()->mapTableName();
         }
       }
reverted:
--- b/core/modules/migrate/tests/src/Unit/MigrateSqlIdMapEnsureTablesTest.php
+++ a/core/modules/migrate/tests/src/Unit/MigrateSqlIdMapEnsureTablesTest.php
@@ -232,8 +232,7 @@
       ->willReturn($plugin);
     /** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher */
     $event_dispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
+    $map = new TestSqlIdMap($database, [], 'sql', [], $migration, $event_dispatcher);
-    $migration_plugin_manager = $this->getMock('Drupal\migrate\Plugin\MigrationPluginManagerInterface');
-    $map = new TestSqlIdMap($database, [], 'sql', [], $migration, $event_dispatcher, $migration_plugin_manager);
     $map->getDatabase();
   }
 
reverted:
--- b/core/modules/migrate/tests/src/Unit/MigrateSqlIdMapTest.php
+++ a/core/modules/migrate/tests/src/Unit/MigrateSqlIdMapTest.php
@@ -111,9 +111,8 @@
       ->method('getDestinationPlugin')
       ->willReturn($plugin);
     $event_dispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
-    $migration_plugin_manager = $this->getMock('Drupal\migrate\Plugin\MigrationPluginManagerInterface');
 
+    $id_map = new TestSqlIdMap($this->database, [], 'sql', [], $migration, $event_dispatcher);
-    $id_map = new TestSqlIdMap($this->database, [], 'sql', [], $migration, $event_dispatcher, $migration_plugin_manager);
     $migration
       ->method('getIdMap')
       ->willReturn($id_map);
reverted:
--- b/core/modules/migrate/tests/src/Unit/TestSqlIdMap.php
+++ a/core/modules/migrate/tests/src/Unit/TestSqlIdMap.php
@@ -6,7 +6,6 @@
 use Drupal\migrate\Plugin\MigrationInterface;
 use Drupal\migrate\MigrateException;
 use Drupal\migrate\Plugin\migrate\id_map\Sql;
-use Drupal\migrate\Plugin\MigrationPluginManagerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
 /**
@@ -29,12 +28,10 @@
    *   The migration to do.
    * @param \Symfony\Component\EventDispatcher\EventDispatcherInterface $event_dispatcher
    *   The event dispatcher service.
-   * @param \Drupal\migrate\Plugin\MigrationPluginManagerInterface $migration_plugin_manager
-   *   The migration plugin manager.
    */
+  public function __construct(Connection $database, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EventDispatcherInterface $event_dispatcher) {
-  public function __construct(Connection $database, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EventDispatcherInterface $event_dispatcher, MigrationPluginManagerInterface $migration_plugin_manager) {
     $this->database = $database;
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $event_dispatcher);
-    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $event_dispatcher, $migration_plugin_manager);
   }
 
   /**