I contacted the author yesterday, and haven't heard back. Can anyone
tell me which language to set it to?
This is what used to be called "Serbo-Croatian", using the Latin script.
After some more research, I think it may be Croatian or Bosniak, as the
author of that page is a Bosniak, but has a blog in the .hr domain.
I tried checking our lxr for the word "Opcije" (Options), hoping to find
which of the existing locales use it, but got no results.
See also
http://en.wikipedia.org/wiki/Differences_in_official_languages_in_Serbia%2C_Croatia_and_Bosnia