The $5 campaign runs from December 15th 2020 to January 13th 2021.
Magento 2 Quick Start Guide, published by Packt.
The source files here are part of app/code/Magelicious
directory.
While the root folder will map to app/code/Magelicious
and show any modules in there, like Core, the rest of directories titled Chatper_* will contain code differences specific to individual chapter.