https://extensions.turbowarp.org/
Set up a local HTTP server on http://localhost:8000/. The experiment will load extensions from there without the sandbox.
If you happen to have Python 3 installed, this is easy:
python3 -m http.server
If you install npm dependencies on your local clone, TypeScript aware editors such as Visual Studio Code will be able to give you smart autocomplete suggestions for most Scratch APIs. Note that these types are not 100% complete and are missing anything TurboWarp specific for now.
npm ci
See CONTRIBUTING.md for more about contributing.