kde-l10n-ru software package provides ru (ru) localization for KDE, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install kde-l10n-ru
kde-l10n-ru is installed in your system.
Make ensure the kde-l10n-ru package were installed using the commands given below,
$ sudo dpkg-query -l | grep kde-l10n-ru *
You will get with kde-l10n-ru package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | KDE |
| Package | kde-l10n-ru |
| Version | 4:15.12.1-0ubuntu1 |
| Description | ru (ru) localization for KDE |
| Sub Section | KDE |