That's your current path. You can usually use relative paths to the main script that you ran -- e.g open('test.jpg') will open the file in the same folder as your script.
In some cases, if you have a module in site-packages, a way to get back to the main script in pythonista isimport sys,os print(os.path.abspath(sys.path))
due to the way that pythonista adds the script that you pressed the play button on to the top of the sys.path.
If you run that little script from a script located in folder inside iCloud folder, it will print out the absolute path, and you can use that in your scripts to write to iCloud. Note, you usually cannot write directly to the iCloud folder itself, you need a subfolder.