This folder is part of the Docker context.

Most of other folders in Airflow are not part of the context in order to make the context smaller.

The Production Dockerfile and the CI one Dockerfile.ci copies the docker-context-files folder to the image context - in case of production image it copies it to the build segment, co content of the folder is available in the /docker-context-file folder inside the build image. You can store constraint files and wheel packages there that you want to install as PYPI packages and refer to those packages using --constraint-location flag for constraints or by using --install-from-docker-context-files flag.

By default, the content of this folder is .gitignored so that any binaries and files you put here are only used for local builds and not committed to the repository.