This might be doable as an add-on as opposed to a modification of the code of the browser itself.
The resulting application will not be called a browser. We'll call it a "Hatch" for now.
1) No address bar. All navigation is by clicking on visual navigation aids (icons etc.)
2) Checks for a valid x.509 identity certificate issued by the Osmio VRD CA ([login to view URL]) in the the user's device
3) Is launch in the same manner as applications such as Zoom are launched from a browser. That is, the "Hatch" replaces the browser on the screen.
Functional specifications are available under NDA.