"The reason Firefox was created was to escape the bloat
from the Mozilla Suite. The creators reasoned that the average web
user didn’t need a mail client, chat client, news client, and
HTML editor. Shocking, right? But the good news is that the
creators also realized that some do need these features. Therefore,
they kept the old Mozilla model of extensions, user-built add-ons
that extend the functionality (or, like the About:IceCream
extension, reduce the functionality) of Firefox."