Adding App Icon to Xcode for Tahoe

I have designed a new icon for my app/Tahoe in Icon Composer (launched from within Xcode)but I simply cannot get it to show up. The documentation for Icon Composer spends a lot of time describing how to design the icons but goes distressingly vague/silent on how one might use it. It suggests that I should drag the file to Xcode and it will guide me as to where to put it.

The app continues to use the old (pre-Tahoe) icon.

I don't get any change of behaviour and I don't know what to name the file. I assume that there are no other settings that I have to change. I can't find anything on the web or in Apple's documentation: maybe I'm missing something obvious!

My app is a working NSDocument-based Cocoa project.

Any suggestions please.

Tahoe 26.0.1, Xcode 26.0.1, Apple M1 Max MBP.

Please see the Configuring Your App to Use Alternate App Icons sample code that demonstrates how to integrate app icons created using Icon Composer.

Adding App Icon to Xcode for Tahoe
 
 
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