I installed 2 of the ones using the Exposure Notification API, just to check what happens in this circumstance (the german app is implemented differently, thoug

I installed 2 of the ones using the Exposure Notification API, just to check what happens in this circumstance (the german app is implemented differently, though) and Android allows access to it to only one app at a time. You can choose/enable/disable manually which app you want to grant access to the api.