Accessing iOS iCloud app data from a Mac?
Try this:  

Go to the ~/Library/Mobile Documents folder. Type anything in the search field in your Finder window. Make sure that Mobile Documents is selected in the Search bar, not This Mac.

Next, click on the + icon, and choose Kind is Document. Go back to the search field and erase what you typed. Now all your iCloud documents will display.

Click on Save, and check Add to Sidebar to add this search to your Finder window sidebars.



Note: one submission said to type a period (.), and, while this starts the search, this may not find all your documents if extensions are not visible. So it's best to start a search, then choose Kind is Document and delete the search.