Adding an intetnal comment on an issue using v3 REST API

Question

I cannot seem to get a good json example for adding an internal comment to an issue.

Tyler Kosaski · Answer

I was having this issue and this was the answer. Thank you.

Bill Sheboy · Answer

Identifier is typically a number representing the text value, and value would be text.  Please try removing one of them, as the error message states.  If you keep identifier, you will need to determine the correct numeric value to use.

Cyberlogic Integration User · Answer

I tried the json as provided and received an error, because it does not provide more information. 
"visibility": { "identifier": "Administrators", "type": "role", "value": "Administrators" },

Is Administrators default for all admins working on issues? 
Or is Administrators specific to some system? 
Where can i see the groups or roles i can specify here?

This is the error i got.

"The body parameters 'value' and 'identifier' are mutually exclusive."
When i remove that part, then it posts the comment, but not only internally.