This documentation provides a comprehensive overview of Piper, the proprietary version control system used to manage Google’s massive Google3 monorepo. It details how developers use CitC to create virtual, cloud-backed workspaces that allow for seamless code interaction without the need for large local downloads. The text explains a trunk-based development model where engineers use changelists instead of feature branches to organize and stage their work. Key operations such as syncing, editing, and shelving are described alongside their equivalents in the Git ecosystem to help orient new users. Furthermore, it outlines the integration with Critique, Google’s code review tool, emphasizing a culture of continuous integration and rigorous automated testing. Ultimately, the sources illustrate how custom infrastructure supports the unique scale and collaborative requirements of one of the world's largest codebases.