Showing links to Contributor Breakdown on Stackoverflow Docs So Stackoverflow Documentation has added "Contributor Breakdown". For any given topic (and example) people can display who contributed in which way. 

That page is only available if you know the link though. And it's not linked publicly in any way. Since I like these hidden pages, but I keep forgetting the correct URLs to use, I wrote a short userscript to insert these links where relevant:

// ==UserScript==
// @name         Documentation contributor links
// @namespace    http://github.com/Vogel612/mini-se-userscripts/documentation-contributor-breakdown
// @version      0.1
// @description  Add links to the contributor breakdown for topics and examples on stackoverflow documentation.
// @author       Vogel612
// @include      /https?:\/\/stackoverflow\.com\/documentation\/.*
// @grant        none
// @run-at       document-end
// ==/UserScript==

(function() {
    // these are in here for debugging purposes
    document.addLinks = addLinks;
    document.addContributorLink = addContributorLink;
})();
// because the page is modified on SE side after loading. 2 secs should be enough to wait
setTimeout(addLinks, 2000);

function addLinks() {
    'use strict';
    let topicLink = document.querySelectorAll("a.doc-topic-link")[0];
    let topicMenuContainer = document.querySelector("div.docs-menu.topic-menu");
    addContributorLink("topic", topicLink.href.split('/')[5], topicMenuContainer);

    let exampleLinks = document.querySelectorAll(".example-link a.doc-example-link");
    let exampleMenus = document.querySelectorAll(".example-link div.example-menu.docs-menu");
    for (var i = 0; i &lt; exampleLinks.length; i++) {
        let currentLink = exampleLinks[i];
        let currentMenuContainer = exampleMenus[i];
        addContributorLink("example", currentLink.href.split('/')[7], currentMenuContainer);
    }
}

function addContributorLink(section, linkId, menu) {
    'use strict';
    let href = `/documentation/contributors/${section}/${linkId}`;
    let elem = document.createElement("A");
    elem.href = href;
    elem.innerHTML = "CB";
    elem.title = "Contributor Breakdown";
    menu.insertBefore(elem, menu.children[0]);
}


Note that the documentation pages are modified by StackOverflow after loading and that removes the link, if I add it before the page is completely built. That's why I run addLinks() with a 2 second delay.

Any and all aspects are up for critique, as always :)
You're using 'use strict'; in all functions except the top one. Why not declare it at the top of your file?

You seem to have thought about readability. You're declaring variables for just that purpose here:

    let currentLink = exampleLinks[i];
    let currentMenuContainer = exampleMenus[i];


So why oh why do I see magic numbers in your code?

setTimeout(addLinks, 2000);
let topicLink = document.querySelectorAll("a.doc-topic-link")[0];
topicLink.href.split('/')[5]
currentLink.href.split('/')[7]
menu.insertBefore(elem, menu.children[0]);


Of those 5, arguably the first and latter are acceptable. The 3rd and 4th are the most magical of the lot. You explained the first in a comment, but I'd personally move it to a variable.