Do GitHub Codespaces not work anymore? GitHub employees encouraged me to make `.devcontainer` definitions for Flask and other projects a few years ago. They did seem useful for new contributors at sprints. It worked, I haven't changed anything, but now creating a codespace hangs and fails after about 10 minutes. Try it here 
click the green Code button, the Codespaces tab, then the green Create Codespace button. #github
GitHub
GitHub - pallets/flask: The Python micro framework for building web applications.
The Python micro framework for building web applications. - pallets/flask