Hi,
Strange but good info regarding BluetoothLE1 "AdvertisementData" block (version 20230728).
For long time I'm trying to use this API / Block with no luck, neither any info about someone who managed to use it.
Recently, I found something strange about this API.
I have an Arduino sensor using HM10 BLE advertising 6bytes HEX data.
Using the HM command: AT+PACK123456789ABC (12 char. of HEX data) I can set the advertising data. I can receive this info by any scanning tool and also a "native" Android application (Java, React), but failed to get this data using the AdvertisementData block.
I'm using UUID- 0000FFE0-0000-1000-8000-00805F9B34FB (the default).
The AdvertiserServiceUuid return only ONE services with the above (expected) UUID, but the AdvertisementData block, return null 
-(
But,
if I'm query the AdvertisementData block with following UUID-
00001234-0000-1000-8000-00805F9B34FB (the first 4 char of the advertising data, the API return the rest of advertising data - [86,120,-102,-68] ..........
It's return as string with int signed values of the original HEX (signed 2's complement ) I post over the HM10 API.
Cut a long story short - If all you need to advertise can by narrow to 4 bytes, you can "freeze" the first 2 bytes of the advertising and use them as your UUID.
Still, not clear why the "correct" UUID return null and why the "fake" service is not listed by AdvertiserServiceUuid ???
Good Luck