Option 2 works so that it additionally saves your .m5b project in the / block or / blocks folder on the device and simultaneously the generated micropython code in the / apps folder on the device.
In uiflow ide you can download your project from the device again to uiflow (the icon next to the button, run "device file manager") and continue editing and make changes.
I generally use 3 options until the program works as I want and then I finally load it to the device using the "download" option.
Coming back to the first option, only the project is saved, i.e. the block arrangement and their parameters. No python code is written anywhere, as it is automatically generated in the uiflow environment and saved only in the second and third cases.
In the third case, only a temporary .py file is saved and launched on the device, but it is not visible in the list of applications. This file stay in flash until its rewriten by next use "run" button.
