What are interesting parts of the Bitcoin Core codebase?

Studying the ProcessMessage function provides valuable insights into the processing of Peer-to-Peer (P2P) messages among other intriguing functionalities. This exploration reveals the underlying mechanisms and the interconnected functions that play a crucial role in the messaging process. By delving into this specific area, one uncovers the complexities and the technicalities involved, offering a comprehensive understanding of how P2P systems operate at a functional level. This knowledge is essential for anyone looking to grasp the intricacies of message processing within such networks.