Created attachment 641749 [details]
Snapshot for a fresh profile.

Integrated Lightning in the Thundebird 38.1.0 from the last official update is
not localized. Its whole UI is in English.

Versions:

MozillaThunderbird-38.1.0-70.57.1.x86_64
MozillaThunderbird-translations-common-38.1.0-70.57.1.x86_64

Steps to reproduce:

1. Update TB to 38.1. It removes the Lightning add-on substituting it by its
integrated version as well as I understand.
2. Start TB in Russian (LANG=ru_RU.UTF-8 LANGUAGE=ru) locale.

Actual results:

Calendar (Lightning) menu items, config options and the whole UI is in English.


Expected results:

Calendar (Lightning) menu items, config options and UI should be in Russian.

The issue is corrected after installing Lightning from a file
(lightning-4.0.1-sm+tb-linux.xpi). But such workaround must make thundebird use
more memory.

The vanilla Russian version
<https://download.mozilla.org/?product=thunderbird-38.1.0&os=linux64&lang=ru>
does not show this issue, so that it is a problem of the OpenSUSE build.