User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0
Build Identifier: 

Ever since the release of Leap 15, I had the issue that the Lightning Calendar would always be shown in English, whereas my system locale is German and Mozilla Thunderbird would also be localized correctly to German. I managed to work around this so far by manually reinstalling the Lightning addon from Mozilla's servers. With every Thunderbird update, however, Lightning would be shown in English again and I would have to repeat the step of fetching the Lightning extension from Mozilla. Now, after the release of Thunderbird 60, the extension package is not easy to find on Mozilla's servers anymore.

So, I tried removing the Lightning addon and reinstalling the packaged version from /usr/lib64/thunderbird/distribution/extensions/ but Lightning remains English. What is strange, though, is that I can see that the folder /usr/lib64/thunderbird/extensions/langpack-de@thunderbird.mozilla.org actually contains localization files for Lightning as well, but somehow they don't get used when running Thunderbird on a German system.

I would like to know how Lightning can and should be localized in openSUSE Leap 15 and how to maintain the localization during package updates.


Reproducible: Always

Steps to Reproduce:
1. Install openSUSE Leap 15 with German localization
2. Install Mozilla Thunderbird
Actual Results:  
When you start Thunderbird, the main interface will be German, but the Lightning Calendar will be shown in English.

Optionally, if you obtain Lightning extension package that includes the German localization and install that manually, Lightning will be localized, but only until the next package update for Mozilla Thunderbird which will lead to the Calendar shown in English again.

Expected Results:  
The Lightning Calendar extension should match the locale of the system (as does Mozilla Thunderbird).