What PHP page powers products_multicolumns.tpl

What PHP page(s) is responsible for powering the products_multicolumns.tpl template page?

index.php powers all the templates on the client side. It runs the index.tpl which runs the main.tpl which runs the content.tpl and so on.

Sorry, I guess I asked the wrong question.

I’m looking for the PHP page that contains the array or query that retrieves the data for products_multicolumns.tpl page.