After I upgraded to grub 2.00.5043-1, I found that grub switched back to English interface because the locale files are missing.
Those locale files used to be in /usr/share/locale but it is not there in the new version.
Is it a mistake, or the upstream just removed those locale files?
I have attached the result of 'tar xf grub-*.pkg.tar.xz' for comparison.
-- Star Brilliant