/**
 * Implements hook_migration_plugins_alter().
 */
function {{ machine_name }}_migration_plugins_alter(array &$migrations) {
  $migrations = array_filter($migrations, function (array $migration) {
    $tags = isset($migration['migration_tags']) ? (array) $migration['migration_tags'] : [];
    return !in_array('Drupal 6', $tags);
  });
}