Tag: attrib	Define an attribute of a new renderer.
Attrib Name	Type	Possible Values	Description
description	string	null	The description of the attribute.
name	string	null	The attribute's name.
onset	string	null	The function or method to call when this attribute is set.
value_desc	string	null	The type of value accepted.
values	string	null	The possible values for this attribute.