xkcd #1288: Substitutions (Cloud To Butt Fork)

Derived from the work of Steven Frank's cloud-to-butt Chrome extension and Chris Wright's Firefox version.

Installing

Download Substitutions.xpi

Building

1. Download the code, open FireFox.
2. Click Add-ons from the Tools menu and select the Extensions tab.
3. Drag-and-drop the XPI file onto the page.