need a suggestion for cart session modification

Hello to all
I want to make a separate page on my website so that customers can save his orders in pdf format. I have search through zen cart, but no session variable is defined for storing the customer cart session. If I had known the session variables or else which stores the customer's cart session, I can easily complete website. Can somebody tell me, how zen cart saves cart session? or could you give the link where I could learn it?

Thank You

As a customer, in your My Account area, you can see all your order history.
The page that shows specific order information is the account_order_history_info
You could pull the data from the database the same way that page does.

Or you could try the popup_printable_invoice contribution, which I think is part of the super_orders contribution. It pulls data similarly, for similar purpose, and could be a starting point for you.