UNIX and Linux Applications

We have been looking into the possibility of configuring firefox upon installation for a common desktop environment for all users. For instance we want the font to be sans-serif 12 points throughout (preferences menu item), a standard set of plugins to be installed (add ons menu item) and some common behavior such as the backspace button to go back (about:config). Ubuntu is one of the distributions that does this right, for example.

I would like to know where to look for the script that does this, so that it can be redone for FreeBSD.
Or perhaps someone has once created a script that can be reused within a FreeBSD environment?

Not entirely sure about FreeBSD, but somewhere in your Firefox installation there should be a "defaults" directory (eg /usr/lib/mozilla-firefox/defaults/), where you'll find the templates for the users profile. Also, parallel to this there should be an extensions directory containing the system-wide add-ons.

Thank you for your response. It is in fact in ~/.mozilla/firefox/
In there the file profiles.ini contains the user profile codes of the profiles that have been set up. Then the individual profiles are in each of the subdirectories [profilecode].default

No. ~/.mozilla/firefox/ is the users personal directory, which is only created when the user first starts Firefox. Check your /usr/share/skel, you won't find a mozilla or firefox directory there (although it might work if you created one). Firefox then uses it's own template directory (/usr/lib/mozilla-firefox/defaults/) to create the profiles.