OAuth with Delta Chat account

I do really like the way one could simply log into this forum with their Delta Chat account.

I would like to experiment with this on my own platforms but can’t find the documentation about it (I may be bad at searching).

So how did you manage to get that running and how could I do the same?

(also, little questions: why are the login bots always different?)

The source code for OAuth bot is at GitHub - deltachat-bot/deltachat-loginbot: A loginbot for OAuth with DeltaChat · GitHub

It is the same bot, it just creates a new group each time. You prove that you have seen the QR code by joining this group.