iCloud Drive Ubiquity Container Folder not showing

Question

I am trying to help users synchronise files created by some other app. So my idea was to have an iCloud Drive folder (like iWork/iLife apps), where the user can save the files from the other app into my app's iCloud Drive folder where I can access the files...

Now, afaik I need to use Ubiquity Containers to do so and so I tried out this example. I was able to get files into iCloud, meaning there is a ~/Library/Mobile\ Documents/iCloud~com~appId~MyApp/Documents folder, I see in Terminal, however there is no folder either in Finder or Files... My code (including Info.plist & .entitlements) is basically the same as the example...

I tried:

• Delete & reinstalling
• restart iOS-device
• turn iCloud Drive off & an again
• increase Build Nr.

There are 2 things that keep me thinking:

1. Is it because I'm in a dev environment and folders only show in prod?
2. I don't have an app icon. Do I need an icon to have an iCloud Drive folder?

If you have any idea feel free to share... Thank you :)