Replicant

I'd expect that something like this can be implemented with an app. It doesn't need to be implemented on the operating system side. Did you investigate if a free app already exists that can do this?

Also it's generally more appropriate to ask for wishlist features in the forums. The issue tracker is for specific bugs.

To be more clear, the main question here is why this cannot be done with an application.

Is there any limitations in the API exposed to applications that prevent doing that or that makes it unpractical to do it?