The Lightning add-on provides calendaring functionality for Thunderbird.
It has been shipped bundled with Thunderbird for many years. We're now
considering to integrate it fully into Thunderbird, by one mean or another.
Once concern is that while many locales are available for both, there
are some locales that are missing in lightning.
The missing ones are
-af (Afrikaans)
-ast (Asturian)
-be (Belarusian)
-cak (Cakchiquel)
-el (Greek)
-fa (Persian)
-hy-AM (Armenian)
-kk (Kazakh)
-pt-BR (there is a pt-PT though)
-si (Sinhala; Sinhalese)
-sr (Serbian)
-uz (Urdu)
-vi (Vietnamese)
If you're a localizer for one of these, I'd like to hear feedback on how
feasible it is for you and your team to get the lightning translation
done too. Next major release is scheduled for next spring (exact
timeframe unknown, maybe around May 2020).
The work is tracked in
https://bugzilla.mozilla.org/show_bug.cgi?id=1493008
It's around 2458 strings to translate in total.
-Magnus