There are many open-source Python projects that can be a great resource for learning and studying the language. Some popular ones include:
Django: A high-level web framework that allows for the rapid development of web applications. It is used by many large companies, such as Instagram and Spotify.
Flask: A lightweight web framework that is easy to learn and use. It is a good choice for small to medium-sized projects and is also used by many companies.
TensorFlow: A powerful machine-learning library that is widely used in academia and industry. Studying the code and examples provided in TensorFlow can help you understand how to implement complex machine-learning models.
Pandas: A library for data manipulation and analysis. It is widely used in data science and is a good resource for studying data manipulation and cleaning techniques.
Scikit-learn: A library for machine learning that provides a wide range of algorithms and tools for data analysis and modeling. It is built on top of NumPy and SciPy, which are also great resources for studying Python code.
OpenCV: a library for computer vision, and image processing, it's widely used for image and video processing and it's a great resource to learn how to use image processing to solve real-world problems.
These are just a few examples of open-source Python projects that can be great resources for learning and studying the language. Remember that the best way to learn is to practice by diving into the codebase, experimenting, and modifying it.