src/vs/workbench/contrib/extensions/browser/extensionsViewer.ts/UnknownExtensionRenderer/renderTemplate
class UnknownExtensionRenderer:	public renderTemplate(container: HTMLElement): IUnknownExtensionTemplateData {
		const messageContainer = dom.append(container, dom.$('div.unknown-extension'));
		dom.append(messageContainer, dom.$('span.error-marker')).textContent = localize('error', "Error");
		dom.append(messageContainer, dom.$('span.message')).textContent = localize('Unknown Extension', "Unknown Extension:");

		const identifier = dom.append(messageContainer, dom.$('span.message'));
		return { identifier };
	}