When the drop-down of options to add an API to a new or existing app, you will find different options for Tracking APIs, among them:
1. The "Tracking" API: This API is designed for a specific Business Unit and is not visible when browsing the API catalog. It is an internal API and approval is not open to external users, hence, there is no documentation provided. Please don't connect to this API.
2. The "Unified Tracking" API: This API offers support for all Business Units. If you are looking for a unique tracking API that will cover most of the DHL services, this might be a good choice.