firefox-esr-l10n-eu software package provides Basque language package for Firefox ESR, you can install in your Debian 7 (Wheezy) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install firefox-esr-l10n-eu
firefox-esr-l10n-eu is installed in your system.
Make ensure the firefox-esr-l10n-eu package were installed using the commands given below,
$ sudo dpkg-query -l | grep firefox-esr-l10n-eu *
You will get with firefox-esr-l10n-eu package name, version, architecture and description in a table
| Distro | Debian 7 wheezy |
| Section | Language packs |
| Package | firefox-esr-l10n-eu |
| Version | 45.4.0esr-1~deb7u2 |
| Description | Basque language package for Firefox ESR |
| Sub Section | localization |