building Icecat and .mozconfig

[Mithat Konar]

In the process of building IceCat 3.6.4 under Debian Squeeze, I noticed the 
bundled .mozconfig is not very short. I want to change some configs in my 
future 
builds (e.g., --enable-system-cairo because I like the font rendering better), 
but before doing so I am wondering a couple things:

1) Where did the original configs come from? The reason I ask is that there are 
a number of options in .mozconfig that are not listed at 
https://developer.mozilla.org/en/Configuring_Build_Options (which itself is not 
very well documented) so I have no idea what some of the options are really 
doing.
2) Which options in particular should I *not* change to maintain IceCat's 
freeness? In other words, changing which options will result in Icecat no 
longer 
being free?

Cheers,
-M