eZ\Publish\Core\FieldType\FieldType::isSearchable PHP Method

    public function isSearchable()
    {
        return false;
    }

 /**
  * Indicates if the field type supports indexing and sort keys for searching.
  *
  * @return bool
  */
 public function isSearchable()
 {
     return $this->internalFieldType->isSearchable();
 }