[luxor]

What is the meaning of $extra in :

{* $Id: dialog.tpl,v 1.25 2005/12/20 08:50:49 max Exp $ *}
{if $printable ne ''}
{include file="dialog_printable.tpl"}
{else}
<table cellspacing="0" {$extra}>
<tr> 
<td align="center" class="DialogTitle">{$title}</td>
</tr>
<tr><td class="DialogBorder"><table cellspacing="1" class="DialogBox">
<tr><td class="DialogBox" valign="{$valign|default:"top"}" align="center">{$content}
&nbsp;
</td></tr>
</table></td></tr>
</table>
{/if}

What does it mean and how to manipulate it?