It’s not a port, it’s a separate implementation. The difference in meaning between these two words is sufficiently important that it’s worth pointing out IMO.

Porting software means to adapt an existing piece of software to a different computing environment.

Ports are based on source code and/or assets from the original piece of software that is being ported.

As such a port would be derivative work, meaning that the authors would not be able to release their software without permission from the copyright holder(s) of the software that was being ported.