Parsing Template Tags (Functions)

[php4ever]

Ok, now a little help understanding then, I'm trying to grasp the structure methodology of vBulletin.

Am I correct in assuming that what looks like php function code in vBulletin is actually what it appears to be? template tags?

What I mean by that is many php programs use template tags such as {template_tag_here} which would parse a specific function specific to that tag. or <?php mosMainBody(); ?> as it is in Joomla for example. In WordPress its quite similar as template tags include things like
<?php get_header(); ?>
<?php get_footer(); ?>

The problem is that it tends to confuse people because it looks like PHP function calls, but in all actuality these are template tags.