This GID was used to exempt users from Grsecurity's `/proc` restrictions; we now prefer to rely on `security.hideProcessInformation`, which uses the `proc` group for this purpose. That leaves no use for the grsecurity GID. More generally, having only a single GID to, presumably, serve as the default for all of grsecurity's GID based exemption/resriction schemes would be problematic in any event, so if we decide to enable those grsecurity features in the future, more specific GIDs should be added.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.