It's because that list is old and has not been updated. It has the predecessor to Cython, Pyrex, but they are very different now.

Both SciPy and NumPy has Cython as a build dependency, and also projects like scikit-learn, scikit-image, statsmodels.

If you find C++ projects which use Swig (wxPython, PyWin32) or SIP (PyQt) it is mainly because they are older than Cython. A more recent addition, PyZMQ, use Cython to wrap C++.

Just to clarify that, while PyZMQ wraps a library written in C++, libzmq's public API is C, not C++. PyZMQ does not use any of Cython's C++ functionality. I have done other similar (unfortunately not public) projects that wrap actual C++ libraries with Cython, and I have been happy with Cython's C++ support[1]. -MinRK [1] At least as happy as I was with the wrapped C++ code, anyway.