History: Mozilla Firefox Support

Easy way for localizers to keep track of en-US article changes -
https://bugzilla.mozilla.org/show_bug.cgi?id=398356
Page not translated notification - https://bugzilla.mozilla.org/show_bug.cgi?id=398354
Simple "Translate this page" functionality - https://bugzilla.mozilla.org/show_bug.cgi?id=398351
"Potentially outdated" flag/status for localized articles
https://bugzilla.mozilla.org/show_bug.cgi?id=398355
Visible status for "potentially outdated" articles.
https://bugzilla.mozilla.org/show_bug.cgi?id=398357

Navigation related...

Remember current locale for in-page article links -
https://bugzilla.mozilla.org/show_bug.cgi?id=398352
l10n URL support -
https://bugzilla.mozilla.org/show_bug.cgi?id=398625
l10n fallback - https://bugzilla.mozilla.org/show_bug.cgi?id=398353

More generic (non-translation specific) requirements:

http://wiki.mozilla.org/Support:PRD