PEPs are Python Enhancement Proposals, and they describe and document the way python language evolves. They also provide a reference point (and a standard) for the pythonic way to write code. This is just the style guide for Python Code.
It was designed to help python developers write more readable code. You can read more about it in at our blog in a posts written by one of our Junior Developers PEP8, and why is it important? - Pragmatic Coders