[bndw]

Does Codespaces support offline development? Is an Internet connection now required 100% of the time to write code?

[int_19h]

It's still a git repo in the end, so you can use all the usual tools to work with it locally.

You can also use https://code.visualstudio.com/docs/remote/containers to run an identical container locally to reproduce the environment, and then connect to it.