src/vs/workbench/contrib/extensions/browser/extensionsWorkbenchService.ts/Extension/defaultIconUrl
class Extension:	private get defaultIconUrl(): string {
		if (this.type === ExtensionType.System && this.local) {
			if (this.local.manifest && this.local.manifest.contributes) {
				if (Array.isArray(this.local.manifest.contributes.themes) && this.local.manifest.contributes.themes.length) {
					return FileAccess.asBrowserUri('vs/workbench/contrib/extensions/browser/media/theme-icon.png').toString(true);
				}
				if (Array.isArray(this.local.manifest.contributes.grammars) && this.local.manifest.contributes.grammars.length) {
					return FileAccess.asBrowserUri('vs/workbench/contrib/extensions/browser/media/language-icon.svg').toString(true);
				}
			}
		}
		return DefaultIconPath;
	}