When Apple releases iOS 13.5 they included their new COVID-19 API that they have been working on with Google to help users easily get alerts if they have been in close proximity to someone who has tested positive for COVID-19. Some countries have opted into this but not all of them.
When enabled, iPhone can exchange random IDs with other devices using Bluetooth. The random IDs your device collects are stored in an exposure log for 14 days. This exposure log allows an app you authorise to notify you if you may have been exposed to COVID-19.
If you are diagnosed with COVID-19, you can choose to share your own device’s random IDs with the authorised app so it can notify others anonymously. COVID-19 Exposure Logging is set to “Off” by default.
Here’s how to opt out of COVID-19 contact tracing in iOS 13.5
Open the Settings app.
Scroll down and tap on Privacy.
Tap on Health.
Tap on COVID-19 Exposure Logging.
Tap the toggle to turn the feature off.