Copybara
Copybara: A tool for transforming and moving code between repositories
...Copybara is particularly useful in workflows where projects maintain both confidential (internal) and public (open source) repositories, enabling controlled synchronization and contribution management between them. The tool supports advanced transformations—such as file relocation, content replacement, and metadata adjustments—defined declaratively in configuration files. It operates in a stateless manner, storing synchronization state within commit metadata to ensure reproducibility and collaboration among multiple users. Copybara currently supports Git repositories (with experimental Mercurial support) and can be integrated with CI/CD systems or run manually.