Why would you need the source? You don't learn much from looking at others code other than how to plagiarize or remove the methods of payment authentication (nulling). If it works fine the use it, as thats probably what your after, don't take the source and plaster your name all over it when it isn't yours, because then once you add all this great stuff to your website someone will call you out on all these php scripts you have been "making" and you won't have anything to help you then.