The pandemic update for iOS 
Disabled by default in iOS13.5 —When you install a public health authority app it will prompt the enabling of Bluetooth-based #COVID19 exposure logging.
#COVID19 Exposure Logging controls before installing any apps in iOS13.5 including any Exposure Checks
Lengthy explanatory text pops up when you tap “Learn More…”
…including this interesting tidbit at the bottom of the scroll
