These sources describe the architectural and technical implementation of fenced frames within the Chromium and Blink engines. Unlike standard iframes, fenced frames function as privacy-isolated embedded pages that utilize separate frame trees to strictly prevent data leakage between a website and its embedded content. The documentation highlights how this framework replaces traditional URL attributes with a secure mapping system involving configurations and properties that redact sensitive information. It further explains the enforcement of communication barriers through network revocation, specialized sandbox flags, and restricted permissions policies. By treating the embedded element as its own top-level browsing context, the system ensures that cross-site data remains protected during ad auctions and storage operations. Ultimately, the text serves as a comprehensive guide for engineers to navigate the C++ classes and privacy logic that maintain this robust security boundary.