To uninstall firefox-esr-l10n-es-ar just follow these instructions.
/debian/stretch/main///install/index.html Spanish (Argentina) language package for Firefox ESR Debian 9.0 localization 45.9.0esr-1
sudo apt-get remove firefox-esr-l10n-es-ar
Which will remove just the firefox-esr-l10n-es-ar package itself.
sudo apt-get remove --auto-remove firefox-esr-l10n-es-ar
This will remove the firefox-esr-l10n-es-ar package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for firefox-esr-l10n-es-ar then this will work.
sudo apt-get purge firefox-esr-l10n-es-ar
Or similarly, like this firefox-esr-l10n-es-ar
sudo apt-get purge --auto-remove firefox-esr-l10n-es-ar
Package | firefox-esr-l10n-es-ar |
Version | 45.9.0esr-1 |
Maintainer | Maintainers of Mozilla-related packages |
Description | Spanish (Argentina) language package for Firefox ESR |
Distro | debian |
Release | stretch |
Repo | main |
Section | localization |