For some obscure reason, my
/var/lib/locales/supported.d/local file contained an extra locale that typically should not be there (in my example,
sudo dpkg-reconfigure locales, and the system reported:
Generating locales... el_GR.UTF-8... up-to-date en_DK.UTF-8... up-to-date en_US.UTF-8... up-to-date Generation complete.
that is, it verified that the rest of the locales are up-to-date; however, there was no mention of the
pl_PL.UTF-8 locale. I don't know if it erased files related to the locale.
How can I make sure that there are no files left in the system for the pl_PL.UTF-8 locale?