Where to look for variables?

Question

PHP

I open
/admin/view/template/catalog/product_form.tpl
it, I see a line there

<?php echo isset($product_description[$language['language_id']]) ? 
$product_description[$language['language_id']]['name'] : ''; ?>

I want to find what the $product_description variable contains. I go to the controller of this template
/admin/controller/catalog/product.php
And I don't find it there. Where can she be?
Here are the template and controller files https://yadi.sk/d/Hg9FvHRrso5B9

Answer 1

for template review_form.tpl default controller is admin/controller/product/review.php