ok

which file 'includes' or 'requires'

/includes/modules/pages/index/main_template_vars.php

basically I am using the multisite add on and would like two versions of that file so that I can display things slightly differently (I am wanting to split the product name and product description for one site but not the other)

option 2 is to rewrite the original template to use the modified main_template_vars

TIA