DT125 RE/X DE06 Rear Fender
hpires rear fender.
I suspect he's blended them in. As in it's a custom fabrication job.
The ones I linked you to are not "hpires" per se. Rather they are copies of hpires.
IIRC - They weren't precisely a direct fit anyhow. And needed some massaging into place.
But that's the general gist.
That bike doesn't look remotely standard!