Chipmunk2D Pro vs. Chipmunk@Github

First, please let me thanks for the great work you have put into Chipmunk.
When evaluating the library I found Chipmunk2D on Github first, after cloning there are few Objective Chipmunk header files in it.
While comparing with the files from the download site
It's obviously some files are missing on the Github clone.
May I know exactly what are the difference them? If one made the iPhone static library (out of the Github clone) into their app, is it legal to redistribute it?
When evaluating the library I found Chipmunk2D on Github first, after cloning there are few Objective Chipmunk header files in it.
While comparing with the files from the download site
It's obviously some files are missing on the Github clone.
May I know exactly what are the difference them? If one made the iPhone static library (out of the Github clone) into their app, is it legal to redistribute it?
