Adds a "View Diff" button to commit pages.

github-commit-diff-link.user.js

// ==UserScript==
// @name           github.com raw diff link
// @namespace      github.com
// @description    Appends raw diff link
// @include        https://github.com/*/*/commit/*
// ==/UserScript==

var container = document.getElementById('toc').getElementsByClassName('explain')[0],
    loc       = window.location + '',
    link      = document.createElement('a');

if(window.location.hash != '')
    loc = loc.replace(window.location.hash, '');

link.setAttribute('hotkey', 'r');
link.appendChild(document.createTextNode('View Diff'));
link.setAttribute('href', loc + '.diff');
link.setAttribute('class', 'minibutton');

container.appendChild(link);