Stacked pull requests are now in public preview

GitHub's answer to a workflow the community has been assembling from third-party tools for years. A stack is an ordered series of small pull requests, each targeting the layer below it, so a large change ships as reviewable pieces instead of one monster diff. Reviewers get a stack map showing where each diff fits; teams can merge a whole stack in one operation or land lower layers early, and the upper PRs rebase and retarget automatically. The preview covers github.com, the CLI (gh extension install github/gh-stack), mobile, and Copilot agents via a gh-stack skill, with merge queue support rolling out over the following weeks. Worth watching for anyone reviewing agent-generated changes too: small stacked layers are exactly the shape that keeps those reviews honest.