self在继承中代表的是当前类还是访问类？

<?php
   class Fu{
       public static $type="Fu";
       public static function getType(){
           echo self::$type." self<br>";
           
       }
   }

   class Zi extends Fu{
    public static $type="Zi";
    
   }
   Fu::gettype();//Fu self
   Zi::gettype();//Fu self
?>

<?php
   class Fu{
       public static $type="Fu";
       public static function getType(){
           echo self::$type." self<br>";//类的静态绑定
           echo static::$type." static<br>";//类的静态延迟绑定
       }
   }

   class Zi extends Fu{
    public static $type="Zi";
    
   }

   Fu::gettype();//Fu self Fu self
   Zi::gettype();//Fu self Zi static
?>