Exchanges can list anything they want...
As far as I remember, Hotbit listing was made right after unlocking the developers coins at the end of summer. I am almost sure that these coins were used to pay for the listing. It does not look like a test coin, right?
At the end of the summer, or rather on August 31, coins were unblocked not by developers, but by early investors and they could not serve as payment, perhaps it was from other funds. more details here
https://scan.idena.io/circulation