C++ Insights is a source-to-source transformation tool built on LLVM/Clang that reveals compiler-generated code by making implicit C++ mechanisms explicit. It processes C++ source through Clang's AST, applies transformations to show template expansions, lambda desugaring, coroutine state machines, lifetime tracking, and other low-level details, outputting valid C++ that illustrates what the compiler does internally. The architecture centers on AST traversal via custom visitors and code generators, with modular components for different transformation modes (standard, Cfront-style, coroutine-specific). Key entry points include Insights.cpp (main driver) and specialized generators like CoroutinesCodeGenerator.cpp. The tool serves an educational purpose, helping developers understand C++ language semantics through visualizing compiler transformations.