AmiTCP (and Miami, Roadshow..) is a very minimal BSD unix kernel running on top of AmigaOS, and as such it has concept of users and groups. Similar concept of users and groups was also in the native LAN package Envoy (but with the unfortunate difference that root uid 0 for posix was “nobody” in envoy, iirc).
OS 3.2 has updates that deals owner and group flags in the filesystem - why this suddenly had become relevant one can only speculate.
