[johnny22]

nrfconnect exposes the services, but if they arent registered with the bluetooth SIG then you won't have much more detail than the ids of characteristics and services and their data types. You won't know what the purpose of each service and characteristic is.

[IshKebab]

You can actually name them, but yeah you can't implement custom encoding/decoding logic. I don't think this thing lets you do that either though.