This is a package that demonstrates the use of new environment markers for Python packaging, following the proposal laid out in tentative PEP 790.

Using ; 'free_threading' in sys_abi_features, one can specify installation of dependencies only for the case of free threaded python. The tentative PEP stipulates a few more possibile markers; for details refer there.

This is implemented through changes in packaging, which are currently in the env-marker-free-threading branch in a fork of gh:pypa/packaging. Because pip uses a vendored copy of packaging, there is a corresponding fork of pip, which contains these changes in the vendored packaging.

The effective working of these new markers is tested in the CI of this repo.