/**
 * Implements hook_system_breadcrumb_alter().
 */
function {{ machine_name }}_system_breadcrumb_alter(\Drupal\Core\Breadcrumb\Breadcrumb &$breadcrumb, \Drupal\Core\Routing\RouteMatchInterface $route_match, array $context) {
  // Add an item to the end of the breadcrumb.
  $breadcrumb->addLink(\Drupal\Core\Link::createFromRoute(t('Text'), 'example_route_name'));
}