I found, that on my home server, running Ubuntu Server 18.04, I've selected quite a few locales, I actually don't need. I only want en_US.UTF-8 and de_DE.UTF-8, since the whole system is configured to use only these.

So, first, I tried the "Debian way" by running dpkg-reconfigure locales and then deselected all besides the two I actually wanted. After that the system automatically regenerates the locales, but, unfortunately, more than I selected:

Generating locales (this might take a while)...

de_DE.UTF-8... done

en_AG.UTF-8... done

en_AU.UTF-8... done

en_BW.UTF-8... done

en_CA.UTF-8... done

en_DK.UTF-8... done

en_GB.UTF-8... done

en_HK.UTF-8... done

en_IE.UTF-8... done

en_IL.UTF-8... done

en_IN.UTF-8... done

en_NG.UTF-8... done

en_NZ.UTF-8... done

en_PH.UTF-8... done

en_SG.UTF-8... done

en_US.UTF-8... done

en_ZA.UTF-8... done

en_ZM.UTF-8... done

en_ZW.UTF-8... done

Then I tried directly editing /etc/locale.gen, but it's all fine in there, since only the two I actually want are not commented out, so it should work. I've checked the file multiple times from top to bottom.

Still, running locale-gen manually, yields the same result as above.

So I wonder if this is a bug or a feature? Is the file maybe cached somewhere or is there another configuration file I'm not aware of? I've already tried restarting the system, but as expected, this didn't change anything.