disable_t.co.user

// ==UserScript==
// @name        Twitter - Disable t.co
// @namespace   localhost
// @description Rewrites links in tweets to not use the t.co shortener.
// @include     https://twitter.com/*
// @version     1.0
// @grant       none
// ==/UserScript==

// We can accomplish this with a MutationObserver.  This will also affect the
// initial page load, because the document mutates a few times during the
// initial page load.
var observerInit = { attributes: false, childList: true, characterData: false, subtree: true };

// because our observerInit tells the observer to ignore attribute mutations,
// this observer's callback doesn't need to disconnect and reconnect the observer
var observer = new MutationObserver( function( objects, observer ) {
 var links, i;
 links = document.querySelectorAll( 'a.twitter-timeline-link[data-expanded-url]:not([data-tco-disabled])' );

 for( i = 0; i < links.length; i++ ) {
  links[i].setAttribute( 'href', links[i].getAttribute( 'data-expanded-url' ) );
  links[i].setAttribute( 'data-tco-disabled', 'true' );
 }
} );

observer.observe( document.body, observerInit );