what is the meaning of this php code in facebook style chat script freichat?
<p>This question is about the facebook style chatting script <a href="http://evnix.com/drupal2/" rel="nofollow">freichat</a> .
The following line is found in arg.php file. Please notice that arg.php is also used in the argument of str_replace(,,.,,) function.</p>

<pre><code>    $parameters=
unserialize(file_get_contents(str_replace('arg.php','config.dat',__FILE__)));
</code></pre>

<p>config.dat file content looks like :</p>

<pre><code>a:20:{s:9:"show_name";s:5:"guest";s:11:"displayname";s:4:"name";s:11:
"show_module";s:7:"visible";s:9:"chatspeed";s:4:"5000";s:5:"fxval";s:4:
"true";s:9:"draggable";s:6:"enable";s:8:"conflict";s:4:"true";s:12
</code></pre>

<p>What does the quoted line actually do? any step by step explanation?</p>
