This lecture covers the theoretical aspects of UX audit, focusing on expert evaluation and benchmarking. It explains the importance of UX audit in detecting design issues impacting usability and user experience. The lecture also delves into the process of conducting heuristic evaluations and the advantages and disadvantages of UX audits. Additionally, it discusses the Bastien and Scapin heuristics, criteria for good design, and the principles of Dieter Rams. The content includes examples of evaluating user interfaces, identifying usability flaws, and interpreting heuristic evaluation results.