Greasy Fork is available in English.
Puts the item ID under the title with buttons for copying it and the cleaned URL
// ==UserScript==
// @name eBay easy item ID
// @namespace pnppl
// @match https://www.ebay.com/itm/*
// @match https://www.ebay.at/itm/*
// @match https://www.ebay.ca/itm/*
// @match https://www.ebay.ch/itm/*
// @match https://www.ebay.co.nz/itm/*
// @match https://www.ebay.co.uk/itm/*
// @match https://www.ebay.com.au/itm/*
// @match https://www.ebay.com.hk/itm/*
// @match https://www.ebay.com.my/itm/*
// @match https://www.ebay.com.sg/itm/*
// @match https://www.ebay.de/itm/*
// @match https://www.ebay.es/itm/*
// @match https://www.ebay.fr/itm/*
// @match https://www.ebay.ie/itm/*
// @match https://www.ebay.in/itm/*
// @match https://www.ebay.it/itm/*
// @match https://www.ebay.nl/itm/*
// @match https://www.ebay.ph/itm/*
// @match https://www.ebay.pl/itm/*
// @grant none
// @version 1.11
// @author pnppl
// @description Puts the item ID under the title with buttons for copying it and the cleaned URL
// @license MIT
// ==/UserScript==
const url = window.location.href;
const reItm = /.*\/([0-9]{12})/;
const itm = url.match(reItm)[1];
const reTLD = /^https:\/\/(?:www.)?(ebay\.[a-z]{2,3}(?:\.[a-z]{2,3})?)/i;
const tld = url.match(reTLD)[1];
const cleanURL = `https://${tld}/itm/${itm}`;
const titleMob = document.querySelector("#vi-frag-app-title");
const titleDesk = document.querySelector(".x-item-title");
const newHTML = ` \
<style> \
button:focus.userjs { \
background:lime; \
} \
</style> \
<div> \
<p> \
${itm} <button class="userjs" onclick="navigator.clipboard.writeText('${itm}')">📋</button> <button class="userjs" onclick="navigator.clipboard.writeText('${cleanURL}')">🔗</button> \
</p> \
</div> \
`;
if (titleMob == null) {
titleDesk.insertAdjacentHTML("afterend", newHTML);
} else {
titleMob.insertAdjacentHTML("afterend", newHTML);
}