iOS AUv3 extension: no Icon shown in host

From the doc:

In iOS, a custom Action extension uses a template image version of its containing app’s icon, which you must provide. iOS Share extensions automatically employ the containing app’s icon. If you provide a separate icon in your Share extension target, Xcode ignores it. For all other app extension types, you must provide an icon that matches the containing app’s icon.

I'm using the AppIcon from my .xcassets file in my containing app. So why doesn't it show in the extension?

It seems I can get the icon to show in Xcode by adding this to the .pbxproj under the extension config: ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;

However the icon still does not show on any host. I guess I have some missing parameters in the Build Settings of the extension.

What asset related entries should I have in the extension build settings for the icon?

To any Apple Dev out there, it seems that I miss some bridge somewhere so that the AppIcon reaches the extension. Maybe in the bundle? Maybe in the build settings? Do I have to include the xassets file as well in the extension?

Thank you in advance for your help!

As of today, it now works by adding the Audio Unit extension to a Swift project.

There’s a new hurdle to clear every day.