Cbc (Coin-or Branch-and-Cut) is a mature, open-source mixed-integer linear programming (MILP) solver written in C++. It functions both as a callable library (via CbcModel and CbcSolver) and a standalone CLI executable, reading standard MPS/LP files and providing a rich set of algorithmic options. The architecture is centered on a branch-and-cut framework with pluggable cut generators (from COIN-OR's Cgl library), heuristics (diving, RINS, Feasibility Pump, etc.), branching strategies, and node selection rules. External dependencies include CoinUtils, Osi, Clp, and Cgl, with optional support for HiGHS, CPLEX, and other solvers through the Osi abstraction layer. The codebase is highly configurable through parameters, event handlers, and callbacks, enabling both out-of-the-box solving and deep customization for research. Beyond the core solver, the repository contains extensive experimental infrastructure, including fixture dumping for deterministic offline replay of cut generation and root-node processing, machine learning pipelines for automatic LP parameter tuning (using LightGBM, XGBoost, random forests), and a suite of performance benchmarks and analysis scripts in Python. This hybrid character makes it equally valuable as a production-grade MILP solver and a platform for operations research algorithm development. The solver is actively maintained by the COIN-OR Foundation, with regular CI workflows and community contributions, though some parts (e.g., the Attic/ directory) contain deprecated or transitional code.