diff -u b/core/modules/migrate/src/MigrationStorage.php b/core/modules/migrate/src/MigrationStorage.php
--- b/core/modules/migrate/src/MigrationStorage.php
+++ b/core/modules/migrate/src/MigrationStorage.php
@@ -170,7 +170,8 @@
               elseif (is_null($migration_value)) {
                 $migration->set($key, $group_value);
               }
-              // Otherwise, the existing migration value overrides the group value.
+              // Otherwise, the existing migration value overrides the group
+              // value.
             }
           }
         }
diff -u b/core/modules/migrate/src/Tests/MigrationGroupTest.php b/core/modules/migrate/src/Tests/MigrationGroupTest.php
--- b/core/modules/migrate/src/Tests/MigrationGroupTest.php
+++ b/core/modules/migrate/src/Tests/MigrationGroupTest.php
@@ -38,7 +38,7 @@
     $migration_group = entity_create('migration_group', array());
     $migration_group->set('id', $group_id);
     $migration_group->set('shared_configuration', array(
-      'migration_groups' => array('Drupal 6'), // In migration, so will be overrideen.
+      'migration_groups' => array('Drupal 6'), // In migration, so will be overridden.
       'source' => array(
         'constants' => array(
           'type' => 'image',    // Not in migration, so will be added.