entity-guids-v2.user.js

// ==UserScript==
// @name         Show Entity Guids
// @namespace    https://www.niche.com/
// @version      1.1
// @description  show entity guids
// @author       Geoff
// @match        https://www.niche.com/*
// @grant        none
// @require      http://code.jquery.com/jquery-latest.js
// ==/UserScript==

(function() {
    'use strict';
    setTimeout(function() {
        if (dataLayer[0].entityGuid) {
            $('#header').append('<div style="position: fixed; top: 20px; right: 20px; color: #53a63a; font-size: 20px; font-weight: 800; background-color: #fff; padding: 20px; border: 2px solid black; box-shadow: 0 10px 6px -6px #777; z-index: 99999999;">' + dataLayer[0].entityGuid + '</div>');
        }
    }, 500);
})();