Let me guess. You saw Alex Xu’s orange book everywhere. You finished Volume 1. Now you need Volume 2—fast. And you saw a Reddit thread mentioning a "free PDF" floating around on GitHub.
If you are preparing for a Senior or Staff-level engineering interview, you have probably typed this exact phrase into Google: "System Design Interview Volume 2 PDF GitHub" System Design Interview Volume 2 Pdf Github Extra Quality
Here is the hard truth: And chasing that ghost will cost you more time than buying the book. Let me guess