It was all in Mozilla first before they decided to separate just the browser from the rest of the stuff.
Yep. So I really ought to have said "parent" instead of "cousin".
I believe the first browser I used was some version of Mosaic. Then went to Netscape, until it became a ridiculously bloated mess that installed crap on my computer in spite of my un-selecting the crap options. Then Mozilla (its descendant, SeaMonkey, is my backup browser). And now the fox. Several versions later, it's a keeper.
Opera is okay but I don't find it as customisable as the fox; Chrome is okay but not something that's going to keep my interest at this stage; and the others I've tried have been discarded almost immediately.