[derhuerst]

> When I changed 'my-awesome-program' to 'ubahnchen' or something else when creating the hafas-client, it stopped getting valid responses.

Please report this as an Issue in the hafas-client repo, so we can discuss this further.

> So I thought I should wait for VBB to give me an ID that works.

This is not how it works: - The official VBB API is an entirely different API, which they give you an auth token for when you ask. - hafas-client uses the "mobile" API, which has a static universal auth token. But it sends a (slightly randomised) User-Agent in order to communicate who/what is making requests. It might be that some User-Agents are blocked.