PHP | ReflectionClass getExtensionName() Function

<?php
 
// Defining a user-defined class named as Departments
class Departments {
    static $Dept1 = 'CSE';
    private static $Dept2 = 'ECE';
    public static $Dept3 = 'EE';
}
 
// Using ReflectionClass over the class Departments
$ReflectionClass = new ReflectionClass('Departments');
 
// Calling getExtensionName() functions
$A = $ReflectionClass->getExtensionName();
 
// Getting the name of the extension
var_dump($A);
?>

<?php
 
// Using ReflectionClass
$ReflectionClass = new ReflectionClass('ReflectionClass');
 
// Calling getExtensionName() functions
$A = $ReflectionClass->getExtensionName();
 
// Getting the name of the extension
var_dump($A);
?>