I can confirm this bug with the Catalan locale (ca_ES.UTF-8), running an up-to-date Alpha 6 installation. While the rest of the desktop applications appear translated, Firefox appears in English (although it has an upstream translation).
I haven't changed the bug status to "Confirmed" yet, as I was not sure for which one of the affected packages it was appropriate.
I can confirm this bug with the Catalan locale (ca_ES.UTF-8), running an up-to-date Alpha 6 installation. While the rest of the desktop applications appear translated, Firefox appears in English (although it has an upstream translation).
I haven't changed the bug status to "Confirmed" yet, as I was not sure for which one of the affected packages it was appropriate.