Discussions on MozillaZine:
What's with Luke Trewin's Firefox Patcher? - MozillaZine Forums
FireFox Speed Patch? - MozillaZine Forums
Apparantly, it just adds tweaks that you can do yourself, using this thread:
Firefox Tuning - MozillaZine Forums. Lots of interesting items in there. I tried some of these tweaks, and found that I couldn't connect to my bank anymore. So, keep note of what you changed.