Bluetooth BLE default advertising UUID

[TravisT]

When using code very similar to the example code (seen below), meaning not adding manufacturing data and service data.

bluetooth.set_advertisement(name='LoPy', service_uuid=b'1234567890123456')

The WiPy starts advertising and before I connect to it, this UUID appears, which does does not match anything I setup.

93DC0A30-7C1A-4222-820E-65282E017BD

My question is how does this get generated? I also do not see the Espressif manufacturer ID, which I would of assumed would be in the default UUID.

741 0x02E5 Espressif Incorporated ( () )

I am still pretty new to Bluetooth so I might not know what I am talking about. Can somebody help clarify where this UUID comes from, and how necessary is it to fill in the manufacturers data and service data on the advertisement packet?

Thanks

[TravisT]

Also for extra reference as I try to piece this together here is what I am finding relevant code references.

pycom modbt.c

pycom-esp-idf, esp_gap_ble_api.c