GitHub repository: sthagen/Nuitka
Primary language: Python
Description: Nuitka is a Python compiler written in Python.  It's fully compatible with Python 2.6, 2.7, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, and 3.9.  You feed it your Python app, it does a lot of clever things, and spits out an executable or extension module.