How to change the sidebar icon of a document that appears in Xcode's documentation browser?

How can I change the sidebar icon that appears in Xcode's documentation browser? I want to change the icon of a document:

Screenshot 2024-02-03 at 03.44.26

In specific I want to use the icon of an extension page like bellow as I wrote my own extension documentation. I don't mind to recreate the icon.

Screenshot 2024-02-03 at 03.44.52

Is there a metadata for it?

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