system
4
Actually, it would probably be more accurate to say that Netscape is derived from Mozilla (at least the later versions, about v4 I think). Netscape released the code about 5 or 6 years ago for people to develop it. Then, when Mozilla releases a milestone version they then take the updated Mozilla code, add there own code such as the integrated AIM & release there own version.
If you don’t want or need the Mail component you could try Mozilla Firebird which is just the browser. It’s smaller & little bit faster than the Mozilla suite.