There are few applications except for Rapidweaver itself.

RapidWeaver - The Macintosh application that is driving all these products
RWMultitool - Edit images in Themes. Note: It was "blocked" from downloading it by Google Chrome. Not sure why. Not installed.
RWThememiner - Edit RapidWeaver themes - From Macupdate.com, not installed.
Stack Installer - When you're having problems installing a stack.