Yarn is a fast, reliable, and secure dependency management tool designed for JavaScript projects. It facilitates the process of managing and sharing code efficiently by ensuring consistent package installations and providing advanced features like workspace support, concurrent operations, and offline caching. Originally released by Facebook, Yarn aims to address issues found in other package managers, such as npm, offering improved performance and predictability. The site at https://classic.yarnpkg.com/ refers to the classic, stable version of Yarn, distinguishing it from other iterations like Yarn 2 (also known as Berry).