vbulletin array ???

[MyPornLife.info]

I found almost in every .php files of vbulletin (faq.php, showthread.php, gallery.php........) thses array

PHP Code:

$phrasegroups = array( 
   // some templates
); 

$specialtemplates = array(
   // some templates
); 

$globaltemplates = array(
   // some templates
); 

$actiontemplates = array(
   // some templates  
); 


actually what r they? why we should use them? what they do? can anyone plz explain me ??