[kbrosnan]

As someone who worked at Mozilla the best way I heard it described is that Netscape designed the embedding to be monolithic. Something you built your app on top of. You best use all of Gecko, NSS, Spidermonkey, etc. Any path that meant your app needed to make changes to Gecko etc. was/is here be dragons territory. If there was some part that your app did not need disabling that part was unsupported and the effort was the the embedding app's responsibility. Where as Chromium was designed to be modular.