ext_unix_group_acl(8) on Linux
The text 3e912e2bff25, as Debian 9 (Stretch) shipped it.
Squid UNIX Group ACL helper
Flags it lists
-
-d -
-p -
-s
The text 3e912e2bff25, as Debian 9 (Stretch) shipped it.
Squid UNIX Group ACL helper
-d
-p
-s