Where do I find the values for each data types in a BLE advert?

Data type values can be found under the generic access profile in the assigned numbers part of the Bluetooth specification as they relate to adverts and discovery. https://www.bluetooth.org/en-us/specification/assigned-numbers/generic-… Data type descriptions can be found in the core specification supplement (CSS) https://www.bluetooth.org/DocMan/handlers/DownloadDoc.ashx?doc_id=302735