Apollo is a comprehensive autonomous driving platform developed by Baidu, providing a full software stack for self-driving vehicles. The repository contains a modular architecture built on Cyber RT, a high-performance runtime framework optimized for autonomous driving scenarios with low latency and high throughput. Key modules include perception (camera, LiDAR, radar, sensor fusion), planning (scenario-based with multiple planners), control (PID, LQR, MPC controllers), localization (RTK, NDT, MSF), prediction, routing, and V2X communication. The system integrates with hardware through extensive driver support for various sensors (Velodyne, Hesai, Continental radar, Mobileye, etc.) and vehicle platforms (Lincoln, Lexus, Geely, etc.). Dreamview provides a web-based visualization and monitoring interface. The codebase demonstrates strong engineering practices with clear module boundaries, extensive configuration management, comprehensive testing infrastructure, and support for both x86_64 and ARM64 (Orin) platforms. Recent versions introduce package management for easier deployment, Dreamview Plus for enhanced developer experience, and cloud-based model training services (Apollo Fuel).