race is first two letters of race's name, all lowercase (case sensitive). Easy to remember, just look left.
category is entirely optional and may be omitted. If category has a value (anything other than whitespace) then it disables the category line on the template being called. This allows the use of these templates without having them categorize the page they are called on, if this behaviour is not desired. (Note that this parameter is part of the original plink templates, so the parameter may be used on those separately if so desired).
This template calls Template:Rp, but has a more descriptive title and parameters to make it easier to understand on main wiki pages. (Rp is as short as possible for use in other templates.)