Opcode Descriptions and Examples
PHP Manual

FREE

PHP code

<?php
/*
 * Release the allocated space of the value.
 * opcode number: 70
 */
 
print "Hello World";
?>

PHP opcodes

Function name: (null)

Compiled variables: none

line#op fetchextreturn operands
60 PRINT   ~0 'Hello+World'
 1 FREE     ~0
72 RETURN     1

Opcode Descriptions and Examples
PHP Manual