This was discussed on netbsd-users a bit over 1 year ago and then
privately with Christos.

On Thu, Jun 21, 2007 at 06:11:21PM +0300, Elad Efrat wrote:
> Brian Ginsbach wrote:
> >Module Name:	src
> >Committed By:	ginsbach
> >Date:		Thu Jun 21 14:09:24 UTC 2007
> >
> >Modified Files:
> >	src/usr.bin: Makefile
> >Added Files:
> >	src/usr.bin/newgrp: Makefile newgrp.1 newgrp.c
> >
> >Log Message:
> >Add the newgrp(1) utility, which changes effective group ID.  This
> >is a POSIX (IEEE Std 1003.1, 2004 / Open Group Base Specifications
> >Issue 6) User Portability Utility.
> 
> where was this proposed?
> 
> -e.
>