Rated 4 out of 5 stars

Από τον/την AbysmalTech στις Ιούλ. 6, 2009 · μόνιμος σύνδεσμος

I'm not sure why Mozilla themselves didn't write a better description, but here is what I got from the project's official page:

"In short, Jetpack is an API for allowing you to write Firefox add-ons using the web technologies you already know."

Source: https://jetpack.mozillalabs.com/