The difference between php$_server[' script_name ' and __file__

$_server[' script_filename ']-------> The absolute path and file name of the current execution program
__file__-------> The absolute path and file name of the original file (included file)

eg
Suppose the Web root is E:/myweb
Build e:/myweb/index.php First
The content is:
<?php require ' other/index2.php ';?>
Re-establish e:/myweb/other/index2.php
The content is:
<?php
echo $_server["Script_filename"];
Echo __file__;
?>
Then visit http://127.0.0.1/index.php and the output is as follows:
e:/myweb/index.php-------------------the absolute path and file name of the current execution program
E:\myweb\other\index2.php-------------------the absolute path and file name of the original file (included)

The difference between php$_server[' script_name ' and __file__