Immuni Detector & Paparazzi attack+camera.
I developed Immuni Detector, an Android app to detect how many users of the contact tracing app Immuni are around you.
Installation: after installation, go in settings->apps->Immuni Detector and enable all permissions for allowing the app to work. Run the app and click Discover. The app also allows to log the time and position of any encounter and thus can be used to perform a Paparazzi attack.
An implementation of Paparazzi attack against Immuni (easily to extend to other apps) can be found here. The new feature is that it can be combined with a camera to automatically take pictures of infected citizens that pass close to the camera. See the instructions in the README.