For those who might struggle with extracting source files on MacOs, here is my solution.
1. Download all source files from Cgcookie and store it at same file
2. We need 7zip unarchiver. I used Keka (download at keka.io)
3. Select ALL files and open with Keka
If you unarchive one by one, it won’t extract blend files with external links for textures etc.
Since I’m a Mac dummy, I spent about an hour to open all source files. I hope you are not a dummy like me! 🤪