What is the function name that updates prices when options are

What is the function name that updates prices when options are selected in the front - which file handles that function and what is its name please?

I said before that you should look in box_product.inc.php script part at the bottom of the file.

This is some client side javascript found here:
https://github.com/litecart/litecart/blob/2.6.1/public_html/includes/templates/default.catalog/views/box_product.inc.php#L255-L285