Initial Developer and Contributors in license block

Hello,

I'm just making a patch to the SeaMonkey file
pref-viewing_messages.xul[1] that has no license block so far. I looked
at http://www.mozilla.org/MPL/boilerplate-1.1/index.html but I'm still
wondering what people I should list under Contributors and who should be
mentioned as the initial developer of that file.

Hopefully someone can give me some insight on the legal stuff.

Bruno

[1]
http://bonsai.mozilla.org/cvslog.cgi?file=/mozilla/mailnews/base/prefs/resources/content/pref-viewing_messages.xul