A PERMISSION HAS TWO LAYERS. The first is given by the browser, the second by you to the product. The «Revoke» button removes the second: the product stops using the permission. The browser permission itself is removed only in its site settings - a page cannot do that on any site, and that is protection, not an omission.
A PERMISSION FORBIDDEN IN THE BROWSER CANNOT BE ASKED FOR AGAIN by the product: the browser will not show the dialogue a second time. It can be given back in the site settings.
Revoking works on THIS device. A permission is given to a particular browser, and on another device it is its own.
A refusal breaks nothing. Every permission says what exactly will stop working and how to manage without it.
The product shows the camera but does not ask for it from this section: turning the camera on just to ask is a sure way to be refused for good. The permission is asked for where a photo is taken.
The location is asked for in the farm profile, when you press to detect the place. If you refuse, the place is set by searching for its name.
Clearing the interface memory does not touch your decisions about permissions.
Erasing the session means signing out of the product: the cookie is deleted by the server, a page cannot reach it.