src/vs/platform/keybinding/common/keybindingResolver.ts/printSourceExplanation
function printSourceExplanation(kb: ResolvedKeybindingItem): string {
	return (
		kb.extensionId
			? (kb.isBuiltinExtension ? `built-in extension ${kb.extensionId}` : `user extension ${kb.extensionId}`)
			: (kb.isDefault ? `built-in` : `user`)
	);
}