What is the default data rate of Nordic BLE, and when is it set in the Thingy code?

[SentinelLighting]

What is the default data rate of Nordic BLE, and when is it set in the Thingy code?  I can't find any reference in the code to what I assume would be NRF_RADIO->MODE!

[Turbo J]

Default BLE data rate on-the-air is 1MBit/sec.