What are group profiles used for and can I rename them?

Summary

What is the purspose of the group profiles

Content

Hi all,

A 3rd party consultant created groups and many are not assigned to account profiles.  We don't event know why there are groups on the first place, how they are linked to an incident, for incident assignment/reporting?  I hope someone can help us with these questions:

Do groups control the incident assignment to accounts?

How can I find if the seemingly unused groups are link/associated to incidents?

How can I find if the seemingly unused groups are link/associated to profiles?

Can we rename a group safely?