Change circle GitHub avatars to square ones

github-square-avatar.user.js

// ==UserScript==
// @name        GitHub Square Avatar
// @author      KevCui
// @match       https://*.github.com/*
// @grant       none
// ==/UserScript==

function changeAvatarStyle() {
    var style = document.createElement('style');
    style.type = 'text/css';
    style.innerHTML = '.avatar-user {border-radius: 6px !important;}';
  
    var avatars = document.getElementsByClassName('avatar-user');
    Array.prototype.forEach.call(avatars, function(avatar) {
      avatar.appendChild(style);
    });
}

window.addEventListener('load', function() {
    changeAvatarStyle();
}, false);