It copies the profile in the Data folder to the My Documents folder and then launches StepMania itself. If there is a StepMania profile in the My Documents folder (this variable is found through the registry), it will rename that folder to SM temporarily. If there is no profile in the Data folder, the default profile is copied to it (this will happen on first launch if you do not put a profile there, instructions below). All EXEs and DLLs were UPX'd by the developers. In the zip file are (non-copyrighted) sample songs and courses.
The program itself is under MIT license (used to be under GNU) and is open source.
This is the latest intermediate (BETA) release (20070325). 'StepMania is a free dance and rhythm game featuring 3D graphics, dance pad support, and a step editor.'