Created attachment 334418 [details] emerge --info net-print/cups-1.5.2-r4 ships with a german localisation in /usr/share/locale/de/cups_de.po. However, instead this localisation file translates everything to empty strings. Instead of displaying any output, cups utilities on my system just display empty lines. As a workaround, setting LC_ALL=C or deleting /usr/share/locale/de/cups_de.po brings back cups messages (english is better than no output).
Fixed, thanks.