Taken from Debian "13-fix-missing-language-field-in-po-files.patch"
--- locale/ru.po.orig	2019-03-06 10:41:55 UTC
+++ locale/ru.po
@@ -13,7 +13,7 @@ msgstr ""
 "PO-Revision-Date: 2009-07-23 08:11+0300\n"
 "Last-Translator: Igor Gorbounov <igor.gorbounov@gmail.com>\n"
 "Language-Team: Russian\n"
-"Language: \n"
+"Language: Russian\n"
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=UTF-8\n"
 "Content-Transfer-Encoding: 8bit\n"