You should contact the author directly in the comments of the file you bought.
Congrats, you have some cool files!
Its best to ask these questions the author directly in the comments where you bought the file.
You should ask your questions in the comments section of the file you bought.
I guess its a mistake, even reviewers are just humans
I guess its called Gaussian Blur, check this: http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
Scary and amazing at the same time!