Apple has put a bullet in JS extensions, so this project is dead.
Github user @Sh1d0w has created an alternative to this project using Safari App Extensions. I haven't tried it yet, but you can find it over here:
Classic README Contents:
Safari extension that strips tracking tokens from the following services:
- Google Analytics (i.e. Urchin Traffic Monitor)
The Google Analytics query string parameters are documented here
Bookmarklet version available here, created by @kid1ng (for use on mobile devices)