Litmus Testing Setup
1. Download and unpack/install (zip) Pre-release candidate of 220.127.116.11. Read the filenames carefully for Linux, Mac or Win32.
2. Install the add on for the build id: Nightly Tester Tools Lite Add On
3. You should run Firefox with a new profile and set up your environment so that you can run different versions of the browser at the same time (in the folder you extracted):
> set MOZ_NO_REMOTE=1 > firefox -profileManager