Add OSM quick actions (Achavi, OSMCha) below change set id.

osm-website-quick-actions.user.js

// ==UserScript==
// @name         OSM-website actions
// @namespace    http://tampermonkey.net/
// @version      1.1.1
// @description  Add few quick actions below changeset id
// @author       praszuk
// @match        https://www.openstreetmap.org/changeset*
// @icon         https://www.openstreetmap.org/favicon.ico
// @grant        none
// @run-at       document-idle
// @downloadURL  https://gist.githubusercontent.com/praszuk/ed5ead5923d089f92d1648b48801ca18/raw/osm-website-quick-actions.user.js
// @updateURL    https://gist.githubusercontent.com/praszuk/ed5ead5923d089f92d1648b48801ca18/raw/osm-website-quick-actions.user.js
// ==/UserScript==

(function() {
    'use strict';

    const extensionSectionElement = document.querySelectorAll('#sidebar_content > div')[0];
    const changesetId = window.location.pathname.split('/')[2];

    const achaviURL = `https://nrenner.github.io/achavi/?changeset=${changesetId}`;
    const osmchaURL = `https://osmcha.org/changesets/${changesetId}`;
    const josmReverterURL = `http://localhost:8111/revert_changeset?id=${changesetId}`;

    extensionSectionElement.insertAdjacentHTML(
        'afterBegin',
        `<p class="quick-actions">
            <a href="${achaviURL}" target="_blank">[Achavi]</a>
            <a href="${osmchaURL}" target="_blank">[OSMCha]</a>
            <a href="${josmReverterURL}" target="_blank">[JOSM Revert]</a>
         </p>`
    );
})();