Those are all just Microsoft Generic Volume License Key's... They are used to install windows and then activate it via KMS. A bunch can be found here [1] and here [2]
Good catch! Most of the generated ones in my test come from those pages (at least the ones I checked). Still, it's curious how it refuses on the first game attempt and then it gives you these anyway when regenerating.
> This key lets you install Windows but won’t activate it — it’s safe and legal for testing or lab setups.