Override for specific title lookups.
File
 
   - drupal/core/modules/views/lib/Drupal/views/Plugin/views/argument/ManyToOne.php, line 199
- Definition of Drupal\views\Plugin\views\argument\ManyToOne.
Class
  
  - ManyToOne 
- An argument handler for use in fields that have a many to one relationship
with the table(s) to the left. This adds a bunch of options that are
reasonably common with this type of relationship.
Definition terms:
Namespace
  Drupal\views\Plugin\views\argument
Code
public function titleQuery() {
  return $this->value;
}