This is the Deno runtime repository, a production-grade JavaScript, TypeScript, and WebAssembly runtime built in Rust with a modular architecture. The system comprises a CLI binary (`cli/`), a core runtime library (`libs/core/`), dozens of Web API and Node.js compatibility extensions (`ext/`), a resolver and npm package manager (`libs/resolver/`, `libs/npm/`), and comprehensive testing infrastructure (`tests/`). The architecture is organized as a Cargo workspace with crates for the CLI, runtime, extensions, and shared libraries. Key entry points include `cli/main.rs` for the `deno` command, `cli/rt/main.rs` for standalone compiled binaries, and `runtime/lib.rs` for embedding. External dependencies include V8, tokio, and various Rust crates; the runtime integrates with npm and JSR registries for package resolution, which is a central data flow alongside module loading and JavaScript execution. The codebase showcases high craftsmanship with declarative op definitions via `#[op2]`, efficient V8 serialization via `serde_v8`, and a pluggable extension system. It has tens of thousands of tests covering unit, integration, spec, and node compatibility scenarios. Despite its enormous size, the code is generally well-structured and actively maintained.