GRUB menu IS in english instead of german when upgrading version 2.06r499…
Quick and dirty WORKARROUND:
copied this file from installed 2.06.r499… to a safe place:
/usr/share/locale/de/LC_MESSAGES/grub.mo
upgraded to 2.12rc1:
replaced the original file by the saved file (that from 2.06.r499)
sudo update-grub
Result: GRUB-menu in geRman again
What is the disadvantage of the solution,
and who can forward the bug to the “responsible authorities”???