I think this has more to do with GNU/Unix design philosophy rather than being an explicit part of FLOSS ideology. Also, you need to remember that GNU/Linux pro

I think this has more to do with GNU/Unix design philosophy rather than being an explicit part of FLOSS ideology. Also, you need to remember that GNU/Linux projects do have a certain amount of control over upstream, seeing as the source is publicly available and can be forked/modified. On the other hand, if Firefox relied on proprietary software, they would be completely at the mercy of decisions made upstream.