Microsoft announced an agreement to acquire GitHub, the world's largest software development platform, for $7.5 billion in stock; more than 28 million developers were then using it. CEO Satya Nadella said "Microsoft is a developer-first company, and by joining forces with GitHub we strengthen our commitment to developer freedom, openness and innovation." Microsoft's Nat Friedman became GitHub's CEO, and founder and former CEO Chris Wanstrath became a Microsoft technical fellow. The deal drew wide attention at the time as confirmation of Microsoft's turn away from hostility toward open source. It also gave Microsoft the largest collection of public source code in existence; GitHub Copilot, released in 2021, would be built on top of it.