Yarn: A new package manager for JavaScript

Introduced Yarn, a new open-source JavaScript package manager developed in collaboration with Exponent, Google, and Tilde. Yarn addresses issues of consistency, security, and performance encountered with the npm client at scale. Key technical contributions include deterministic dependency resolution using lockfiles, a global cache for offline installs and faster fetching, parallelized installation steps (resolution, fetching, linking), and a mutex for concurrent CLI instances. Yarn aims to provide a faster, more reliable, and secure alternative to npm while remaining compatible with the npm registry.