Why don't Google and Apple co-operate and develop the app and roll it out as a critical public safety update across the globe?
They could have done this months ago.
It would save countries across he whole world duplicating effort and going down rabbit holes. And think of the number of lives it could have saved / would save.
And the app would also work once international travel resumes.
They routinely push out updates that help them maintain their not so insignificant income streams.
They have the technological prowess to make it happen.
About time they did something that gives something meaningful back to the public.