Today I received this email from
bart@mozilla, so lets hope this helps
Hi George,
We definitely want to work with the Debian project such that Debian
includes a copy of Mozilla Firefox that is named as such and includes
our official logos.
Our main concern is that, if we make our logos available as part of the
source code that's licensed under the MPL, that would invalidate our
trademarks.
Asa and Ben here are also interested in helping to work out a solution
that works for everyone.
Asa: have you been talking to Debian people about this issue?
Bart