Sapling is a new Git-compatible source control client that prioritizes usability and scalability, even for the largest repositories. Meta has invested heavily in building a world-class source control experience over the past 10 years, resulting in the creation of Sapling. This user-friendly system provides unique features such as the smartlog command, which simplifies the understanding of repository changes, and tools for easily fixing mistakes. Sapling also supports stacking commits for more efficient review processes within large organizations. The client is just the beginning of a larger plan to open-source the entire system, including a virtual file system and a scalable server.
https://engineering.fb.com/2022/11/15/open-source/sapling-source-control-scalable/