Before this commit it was possible to build a guix home configuration where home-environment-variables-service-type could ungexp any file-like object such as a package. The commit 73684dc90 forces it to be a string, which contradicts the documentation for guix. 

Concretely, guix home environment test-home.scm worked before that commit where test-home.scm is attached to this email.

-- 
 Regards,
Kabelo M'sobomvu Moiloa