Volunteer translators on BabelZilla have a kind of niche activity but their work is pretty much exposed, at least for most popular extensions.
So they do their best to achieve quality (which is endless pursuit) and consistency with the interface of the application the extension should mingle with.
As you probably noticed, recently Firefox UI switched from Status Bar to Addon Bar (for more or less valid or controversial reasons, but that is not my point here) so your translations should match this new name!
Open your brand new Firefox, right-click on any bar and see how Add-on Bar is now translated.
Else, you are welcome to use Transvision tool: pick your own language on this page, search for “Add-on Bar”, see how Mozilla l10n team (mmmh some of you are part of it 😉 ) has already translated it and change accordingly.
And by the way, developers should change labels as well 🙂