This is hard. Re-implementing something similar to what Android does. The user interface needs to be to show elements (security question) which cannot be faked by the application. I.e. if a malicious application would overwhelm the user with questions in order to trick the user into giving an additional permission.
This is good since it breaks down difficult syntax into more human readonable configs.
How would any application use that?
Stackable Wrappers issue?
Popup during installation of what? Package? That won’t be good. There are no packages which use a GUI to ask questions. Please also keep headless systems in mind (even if just skipping any questions there). Also asking the user security questions is mostly a bad idea. I guess we’d have to pre-configure this for some applications?
What about new applications? How would sandbox-app-launcher notice that there’s a new package (or even binary/appimage in user home folder) and then ask the user security questions? Not necessarily an issue you need to solve. I guess the user needs to be aware of sandbox-app-launcher and wanting to use it manually?
Also GUI applications shouldn’t be writing files into /etc. None of packages from package.debian.org do that.