BI Publisher - sub-template use

Newly using BI Publisher and have a hopefully simple question:

I know I can use sub-templates generated and saved in the Content Library

and I see in the documentation in PeopleBooks that you can use a template by a call using <?call-template:peoplesoft?>

When I look at XRFWIN as an example, I see <?call-template:portrait?>

Where does the "portrait" template exist??

I am wondering what else there is to that opton ... landscape, executive, legal (A4 ... A6)  and maybe more ... but I can't find where they are.

Thanks,

John