Taking your code and leaving

There is no export step, because there is nothing proprietary to export from.

Your app is ordinary source code in an ordinary format, and every saved version is part of its history. There is no proprietary format and no export process.

Clone it and run it anywhere. The one thing that does not come with you is the managed storage and its settings, since those are ours to run — the details you need to connect are yours, and how your information is organised travels with your code.