Google's Rust Style Guide Goes Public

This is less a formatting document than an operating standard for Rust at monorepo scale—and a useful specification for both human reviewers and AI coding agents.

• –Extends beyond rustfmt into API design, error handling, traits, ownership, concurrency, and unsafe-code discipline
• –Optimizes for large-scale refactoring with small crates, flat Chromium layouts, explicit imports, and predictable naming
• –Favors maintainability through `non_exhaustive` public APIs, `expect` over `unwrap`, contextual assertions, and documented safety boundaries
• –Balances Google-specific rules with the broader Rust Style Guide and Rust API Guidelines
• –Gives coding agents a concrete style target, though automated enforcement and meaningful review remain essential