Solaris

You can't tell, what a group is good for, from just looking at the group name, like you cannot tell, what a specific key is good for, before you know all locks.

A start would be to check for files or directories on the system that belong to a group in question. Membership in a specific group could entitle you to read or write certain data or execute programs.

But there are also uses of groups that you can not find just from the operating system point of view. In DB2 for example, you can grant rights to database objects based on operating system group membership.

So I am afraid, it is not possible to answer your question

Each file on a Unix filesystem belongs to a user and a group.
When you are accessing to the filesystem, you are also having a single user identifier and a single effective group identifier. Run the "id" command to see them.
Each file has also read, write and execute permissions for its owner, its group and others (eg: rwxr-xr--).
If you are the file owner, the first set of permissions apply, here you can read, write and execute the file.
If your current group is the same of the file the second set apply, here you can read and execute the file but not write (modify) it.
Otherwise, the last set apply. You can only read the file.
You change (i.e. login) to a new group with the newgrp command.

ACLs are an alternative, more modern and flexible way to grant attributes to users.

Yes. Thank you ..
I do understand id ... and the format of /etc/passwd and/or /etc/shadow .. not too much help here though.

Hummm ... tough. I cant open a ticket with the admins asking that they either remove me or add me to/from any group without being able to define what they are.

I guess Ill just leave them alone. But you know .... it just bothers me ... I like to keep my stuff tight ... know ?

Thanks to all.

This looks pretty pointless. How would the rest of us know what these secondary groups allows you to do ?