A userscript for StackExchange that adds a link to the question's timeline below the question.

SE_timeline_link.user.js

// ==UserScript==
// @name         StackExchange timeline link
// @description  Adds a link to the question's timeline below the question
// @version      1.2.8
// @author       Paul Pinterits
// @include      *://*.stackexchange.com/questions/*
// @include      *://meta.serverfault.com/questions/*
// @include      *://meta.stackoverflow.com/questions/*
// @include      *://meta.superuser.com/questions/*
// @include      *://serverfault.com/questions/*
// @include      *://stackoverflow.com/questions/*
// @include      *://superuser.com/questions/*
// @exclude      *://*/questions/tagged/*
// @exclude      *://*/questions/originals/*
// @exclude      *://*/questions/ask
// @require      https://github.com/Aran-Fey/userscript-lib/raw/ca6999d1bac2494421b70286f74d7a9a9ba636e7/userscript_lib.js
// @require      https://github.com/Aran-Fey/SE-userscript-lib/raw/bf77f40b25d7fa88a6c3f474390c858446154ec2/SE_userscript_lib.js
// @grant        none
// @updateURL    https://gist.github.com/Aran-Fey/45a57f81c2ab4345dd7c95993d15b952/raw/SE_timeline_link.user.js
// @downloadURL  https://gist.github.com/Aran-Fey/45a57f81c2ab4345dd7c95993d15b952/raw/SE_timeline_link.user.js
// ==/UserScript==


function add_timeline_link(post){
    let timeline_url = post.timeline_url;
    
    let post_menu = post.menu_element;
    if (post_menu.lastChild.href === timeline_url)
        return;
    
    let sep = document.createElement('SPAN');
    sep.classList.add('lsep');
    sep.textContent = '|';
    post_menu.appendChild(sep);
    
    let link = document.createElement('A');
    link.textContent = 'timeline';
    link.title = "show this post's timeline";
    link.href = timeline_url;
    post_menu.appendChild(link);
}

page.transform_posts(add_timeline_link, Rerun.AFTER_CHANGE);