What is a client-id?

[dterefe]

Hello, i know this is probably trivial, but I do not find any reference to a "client-id" connected to my current iCloud account. Do i require a developer account to use this API and that is how I get access to a client-id? Furthermore, when using the Python API for iCloud on which this API is based on, I don't need a client-id and can just use my normal login data to sign into iCloud.

Can someone explain what the client-id is and where I can get it to use this API?