> I would put this front end either in non-US or in main, because
> it is not a bad thing for main packages to point to it.
"Bad" is not the issue. The issue is that main is self contained, and can
be installed without anything else but main.
I see no particular virtue in this. Pointers from main to non-free
software is a problem for specific reasons; pointers from main
to free non-US programs are not a problem.