API ref for hook_entity_diff_alter() doesn't list $entity_diffs as by ref

From diff.api.php:

/**
 * Allow modules to alter a comparison about entities.
 *
 * @param array $entity_diffs
 *   An array of entity differences.
 * @param array $context
 *   An associative array containing:
 *   - entity_type: The entity type; e.g., 'node' or 'user'.
 *   - old_entity: The older entity.
 *   - new_entity: The newer entity.
 *   - view_mode: The view mode to use. Defaults to FALSE.
 *
 * @see hook_entity_diff()
 */
function hook_entity_diff_alter($entity_diffs, $context) {
}

$entity_diffs needs to be passed by ref so that changes can be made to it.