In hopes of honoring this request, I just looked at the heimdal sources in debian. I cannot find evidence of the includedir or include krb5.conf directives there even in 2022. Unless I'm missing something I still don't think it makes sense to add this to Debian without heimdal support.
- Bug#858970: Still not in Debian Sam Hartman
- Bug#858970: Still not in Debian Russ Allbery