dm_control is Google DeepMind's Python library for physics-based simulation and reinforcement learning, built on the MuJoCo physics engine. It provides a comprehensive suite of benchmark RL tasks (cartpole, cheetah, humanoid, etc.), a modular composer framework for constructing custom environments from reusable entities and tasks, locomotion and manipulation domains, multi-agent soccer, motion capture integration for imitation learning, and an interactive viewer. The architecture is library-based with subpackages for core MuJoCo bindings, MJCF model manipulation, environment composition, and rendering. Key entry points include suite.load() for standard tasks, composer.Environment for custom environments, and viewer.launch() for interactive visualization. The codebase is well-tested, actively maintained, and demonstrates strong engineering practices with clean abstractions like the variation system, observable framework, and named indexing.