== O:3:"Car":1:{s:4:"name";s:7:"new car";} object(Car)#3 (1) { ["name"]=> string(7) "new car" }请问为什么是这样的输出结果 啊，我看不懂

<?php

class Car {

    public $name = 'car';

    public function __clone() {

        $obj = new Car();

        $obj->name = $this->name;

    }

}

$a = new Car();

$a->name = 'new car';

$b = clone $a;

if ($a == $b)  echo '=='.'<br>';   //true

if ($a === $b) echo '==='.'<br>'; //false

$str = serialize($a); //对象序列化成字符串

echo $str.'<br>';

$c = unserialize($str); //反序列化为对象

var_dump($c);