You can use this repo for reference: https://github.com/mohsen1/llm-debugger-vscode-extension

In package.json for this extension, the icon properties are missing for viewContainers and views that it contributes. When you run the extension, you get the following error message:

I probably spent an hour trying to "fix" the top level icon property in package.json to no avail since it wasn't the culprit :). It wasn't until @isidorn pointed out to me that these contributions also needed an icon property. You can see the "fix" here:

Suggestion: Can we show validation on one or more of the contributes properties in the file, similar to how there is validation on activationEvents "*" that give the user some indication of where the missing properties are?

Assigning per Isi's recommendation.