Companies, governments, etc. can track Bluetooth and WiFi network scans passively by looking at a same MAC address over space and time (Bluetooth/WiFi Identity tracking in public spaces - How to discover?). Starting in Android 8.0:
Android devices use random MAC addresses when probing for new networks while not currently associated to a network.
In Android 9, a developer option can be enabled (it is disabled by default) to cause the device to use a randomized MAC address when connecting to a Wi-Fi network. A different randomized MAC address is used per SSID.
MAC randomization prevents listeners from using MAC addresses to build a history of device activity, thus increasing user privacy.
Can something similar be implemented for Bluetooth MAC addresses? Is it implemented at start-up or do these addresses rotate periodically?