User route

Route

luberri.nor:
  path: '/nor/{user}'
  defaults:
    _controller: '\Drupal\luberri\Controller\LuberriController::nor'
  requirements:
    _permission: 'access content'
  options:
    parameters:
      user:
        type: entity:user

Controller

use Drupal\Core\Controller\ControllerBase;
use Symfony\Component\HttpFoundation\Request;
use Drupal\Core\Session\AccountInterface;

Controller function

  public function nor(AccountInterface $user, Request $request) {

    $build['sarrera'] = array(
      '#theme' => 'luberri-nor',
      '#selected' => $user,
    );

    return $build;
  }