For anyone else coming later, if you need to modify these files to test out for instance a code fix you would use the CLI tool to run cloudron debug --app app.domain.com, open a web terminal to the app, edit whatever files you need to in /app/code, and then run /app/pkg/start.sh from within that web terminal to manually start the app and test your change.
You can exit debug mode, which will delete your changes, by going to the app's settings in cloudron, Repair, and clicking the Disable Recovery Mode button.
