[Closed] Add command to the viewport label menu

Hey,
I would like to make a new entry to the viewport menu. I mean the menu you get when you right click on a viewport label in the upper left corner of a view. Furthermore I want my new menu item only to be shown when the viewport is a camera, such as “Select Camera” is only available when the viewport is a camera view.

I can’t find any access to that view menu… Does anyone know how to get there? Thanks