We touched on the reasoning for the use of Pattern Lab in the SiteFarm project in our article "An Introduction to Atomic Design and Pattern Lab in SiteFarm" but let's discuss some of the details of why we organized the file structure the way we did, where to find important code, and how we develop within this environment.
The backbone of the SiteFarm theme is a solid front-end design. This code for that design is kept inside of a framework called Pattern Lab that allows us to design, review, and share the look of the theme outside of the SiteFarm CMS.