OK, I understand. You're looking primarily at the template level rather than page initialisation and data prep.
In that sense the product info template does a similar job to the main page template, but just for the center panel (the main page template is still taking care of the overall page structure and there are other templates looking after the header, footer, sideboxes, etc.)
It's not the only file however, as if you look inside it, it loads other template files as it needs them.
These together will cover most of the content on the page, however some of the HTML for attributes is generated by the includes/modules/attributes.php file.
For styling though, code inspection is still not the best way to find out what tags and selectors are available. Better is a tool such as Firebug, or the developer tools in IE8 and Google Chrome that allow you to inspect each element and understand what is available to hang your css on, and even try it to see if it will work.