cibuildwheel is used to build wheels for tagged versions of Pillow.
This directory contains multibuild to build dependencies for macOS and Linux wheels, and dependency licenses to be included.
https://github.com/python-pillow/pillow-depends contains archives for libraries that will be built as part of the Pillow build.
In general, there is no need to put library archives there, because the
multibuild scripts will download them from their respective URLs.
But, the build will look in that repository before downloading from the URL, so if there is a library that often fails to download, or you think might fail to download, then download it and add it to the Git repository.
See build in .github/workflows/wheels-dependencies.sh and the fetch_unpack
routine in multibuild/common_utils.sh for the logic, and the build recipes in
multibuild/library_builders.sh for the filename to give to the downloaded
archive.
Wheels are GitHub Actions artifacts created for tags, relevant changes or manual builds.