这条线是什么？

I am working on a template a friend given me ages ago. However, this is the code of the main page:

<div class="span4">
                    <div class="widget">
                        <div class="navbar"><div class="navbar-inner"><h6>fame</h6></div></div>
                        <div class="well body">
                            <center>
                            <div class="fame">
                                <?php include("cache/fame.php"); ?>
                            </div>
                            </center>
                        </div>
                    </div>
                </div>

In this fame.php, there's a line of code:

    if(!isset($_GET['enable']) && !isset($argv[1]) == "enable")
{
    echo 'Invalid request';
    return;
}

And it always return Invalid request from the main page.. So, what is this last code paragraph for?

   if(!isset($_GET['enable']) && !isset($argv[1]) == "enable")
{
    echo 'Invalid request';
    return;
}

The above code is used in 2 scenarios: One is the script mode for which the argument $argv is used. Second mode is as server code where Global params are being passed i.e $_GET.

Just change the code to handle both the scenarios.

if(php_sapi_name() == 'cli' && (!isset($argv[1]) || ( isset($_GET['enable']) && $argv[1] !== "enable"))

{
    echo 'Invalid request';
    return;
}
else
{    
 if(!isset($_GET['enable']) 
 {
    echo 'Invalid request';
    return;
 }
}