Hi,
I have on different occasions had the issue of the package manager Guix hinting that locales were not installed or that GUIX_LOCPATH was not set, even though they were. Today I went to the bottom of the issue [0] and have found what in my opinion is the root cause:
Despite its name, the package glibc-utf8-locales does not contain all utf8-locales. There is nothing in the name that makes this apparent to the user, especially given that the package named glibc-locales contains all locales.
My suggestion then is to change this package name from glibc-utf8-locales to glibc-limited-utf8-locales to make this distinction apparent to the user.
The package name was mentioned enough times in the code of guix that I hesitate to submit a patch with s/glibc-utf8-locales/glibc-limited-utf8-locales/ run over the codebase. But perhaps it is that easy.