What is this?

  class User 
  {
    /**
     * @Assert\All({
     *     @Assert\NotNull,
     *     @Assert\Length(min=5)
     * })
     */
    public string $name = '';
  }
  PHP 8.1
  class User 
  {
    #[\Assert\All(
        new \Assert\NotNull,
        new \Assert\Length(min: 6))
    ]
    public string $name = '';
  }