Hi, Cinder <https://github.com/facebookincubator/cinder> is Meta’s performance-oriented version of CPython 3.8. It has been in use as the production Python behind Instagram server for years, as well as powering various other Python applications across Meta. We are interested in making the improvements in Cinder more broadly available to the Python community. As a collection of features and components built on top of CPython, we’d like to: 1. Merge the feature into CPython for core features that are highly coupled with CPython internals (after we port it over to the main branch) 2. For features that *can* work as extension modules (like Cinder JIT) - extract them as a new open source standalone pip-installable extension module. 3. To enable the pip-installable extension module, we will need to add a few extension hooks to CPython, which we intend to carve out and port over to the main branch in order to merge upstream. Please read more about our upstreaming strategy and a few Cinder features in this document: https://docs.google.com/document/d/1l8I-FDE1xrIShm9eSNJqsGmY_VanMDX5-aK_gujh... Complete source code of our CPython fork: https://github.com/facebookincubator/cinder We started filing bpo issues for a few of the pieces we want to merge upstream (links are in the google doc), and are looking forward to feedback from the community on the issues, overall approach, or any feedback on the features themselves. Cheers, Dino