Good for Firefox
You have to give credit to Mozilla to play the "Hey, here's our code, have at it" card when it comes to proving they are neutral when it comes to government interference. I think a lot of users woke up a bit when they saw Chrome wasn't as secure as they would've liked to think, and so Mozilla promoting Firefox as a safe alternative is a great marketing move. I don't expect other browser code to be as forthcoming, especially from major providers who have agreements with government entities.
I wonder if they would repeat this when it comes to talk of their Firefox smartphone... I'd be curious to see if similar claims could be made as to the validity of the O/S.