What is private ticket and private note - For translation more explicit

[ZerooCool]

For translation :

On this page : https://redmine.domaine.fr/projects/project_name/settings/messenger

Can you explain to me the role, in the second block, of the last two options: private ticket and private notes.

Is a ticket a redmine issue? What does private mean?
A private note, what does it correspond in redmine?

[ZerooCool]

I see :
a private ticket is therefore an issue of redmine, with the case private box checked.
a private note is a response to a ticket, with the private box checked.

A text field could be added, to explain (or recall) what it means, below the check boxes.

It would be necessary to create 2 more lines, in each language file, and, add the explanation in parenthesis, under the check box, or, on the right of the check box.