This directory is a collection of files that have been mirrored from their original locations. setup.py is responsible for performing the mirroring.
These files are necessary config files (e.g. native_functions.yaml) for torchgen to do its job; we mirror them over so that they can be packaged and distributed with torchgen.
Ideally the source of truth of these files exists just in torchgen (and not elsewhere), but getting to that point is a bit difficult due to needing to deal with merge conflicts, multiple build systems, etc. We aspire towards this for the future, though.
Note well that although we bundle torchgen with PyTorch, there are NO BC guarantees: use it at your own risk. If you're a user and want to use it, please reach out to us on GitHub.