src/vs/workbench/services/themes/common/workbenchThemeService.ts/fromJSONObject
	export function fromJSONObject(o: any): ExtensionData | undefined {
		if (o && isString(o._extensionId) && isBoolean(o._extensionIsBuiltin) && isString(o._extensionName) && isString(o._extensionPublisher)) {
			return { extensionId: o._extensionId, extensionIsBuiltin: o._extensionIsBuiltin, extensionName: o._extensionName, extensionPublisher: o._extensionPublisher };
		}
		return undefined;
	}