note that what more or less happened is that some samsung guys dropped the code and mozilla was like "oh hey cool thanks!" and also "lets talk about this!" because talking about this - servo, rust that is - is a good thing anyway - even thus samsung probably develop stuff on their side in the dark and suddenly drop code.
rust is a pretty damn nice language. its fast and safe. C++ kind of fast. And servo attempts to implement everything a modern browser should ideally be.
Also, Contrarily to comment 2.. Mozilla actually.. develop and take decisions fully in the open. Heck even the security reviews are public. The security meetings.. are public. It's not about the source code being open, but their whole process is open. You can participate to decisions if you want. Not by commenting here, not by posting a single bug (although if its really insightful, people will certainly take it into account), but by actively taking part of the project (this does take time) and make your voice heard.
I'm sure Mozilla isn't perfect (far from it) and some people there either, but its pretty damn nearer to my ideals than other companies, personally. At least they seems to really attempt to "do no evil". The corporation is governed by a foundation, everything's open and they usually fight for privacy and user control against the odds.