6 files declare their use of Merge

DatabaseStorage.php in drupal/core/lib/Drupal/Core/KeyValueStore/DatabaseStorage.php: Contains Drupal\Core\KeyValueStore\DatabaseStorage.
DatabaseStorageExpirable.php in drupal/core/lib/Drupal/Core/KeyValueStore/DatabaseStorageExpirable.php: Contains Drupal\Core\KeyValueStore\DatabaseStorageExpirable.
Merge.php in drupal/core/lib/Drupal/Core/Database/Driver/mysql/Merge.php: Definition of Drupal\Core\Database\Driver\mysql\Merge
Merge.php in drupal/core/lib/Drupal/Core/Database/Driver/sqlite/Merge.php: Definition of Drupal\Core\Database\Driver\sqlite\Merge
Merge.php in drupal/core/lib/Drupal/Core/Database/Driver/pgsql/Merge.php: Definition of Drupal\Core\Database\Driver\pgsql\Merge
MergeTest.php in drupal/core/modules/system/lib/Drupal/system/Tests/Database/MergeTest.php: Definition of Drupal\system\Tests\Database\MergeTest.