The problem is that you made big changes in mozilla-firefox but the version number was not correctly changed. My locale packages doesn't check for update-mozilla-firefox-chrome, but they depend on mozilla-firefox << 1.0.999. I would expect a major version change for a major change in the package. Current 1.4.99+1.5beta1.dfsg-1 is fine, but not 1.0.99+deerpark-alpha2-1. Now we get some bugs about broken extensions: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=327742
We should coordinate better in the future. César