New instance of Nextcloud 28.0.3 already contains unknown contacts?

I just finished setting up a fresh instance of Nextcloud 28.0.3 (Ubuntu 22.04LTS, Apache2, MariaDB, PHP8.1).
I used the NC community Archive

I haven’t yet added any devices or the NC client but when I checked the Contacts app I noticed that it contains three strange and unknown emails.
I am also unable to delete them (not given an option to delete).

If I try to delete the Address book which contains them I am denied:

Deletion of address book was not successful.