How to change language interface in Mozilla Thunderbird

SOLUTION!

1. looking for language file (.xpi) sample https://download-installer.cdn.mozilla.net/pub/thunderbird/releases/60.5.3/win32/xpi/ru.xpi

2. In thunderbird open the manage add-ons  «Tools → Addons».

3. «Install Add-on From File…».

4. To choose .xpi file

5. «Advanced → Main → Config Editor».

6. to looking for string intl.locale.requested 

7. Change his value , sample  en-US to ru