Synthesized answer
The provided passages do not contain information about what questions remain unanswered. They describe the book "System Design Interview - an Insider's Guide" by Alex Xu and Sahn Lam, highlighting its content and structure [1].
The passages state that the book includes a 4-step framework for solving system design interview questions and 16 real system design interview questions with detailed solutions [1]. However, they do not list any specific questions that are left unanswered within the book itself or any questions that the book aims to answer but doesn't.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: System Design Interview - an Insider's Guide by Alex Xu, Sahn Lam Description: An insider's take on what interviewers are really looking for and why including: a 4-step framework for solving any system design interview question and 16 real system design interview questions with detailed solutions.