A wild Mutantstang in the USA

[V8 Fireworks]

Here's somebody's video of their trackday at COTA in an old NSX. Nothing remarkable there, but check the bottom left-hand-corner: they are passed by what's clearly an Australian-spec Mutantstang which seems to be missing the top level of it's rear wing.

https://youtu.be/pyRU9PLqM5I?t=496

With that distinctively mutated look, it certainly can't be mistaken for a racecar based on an actual Mustang.

How did it get there? Was it an old Falcon or Commodore COTF V8 Supercar that was converted?

It was reported that some cars went over for the Team Penske museum, one being used for a demonstration by Ryan Briscoe, but it seems most unusual that other Mustangs with that distinctive Gen 2 composite bodywork would end up randomly in the US.

So is it a case of secret testing conspiracies? Four-shaker rig conspiracies (since I believe sending cars over to do shaker rig testing in the US or anywhere else was banned quite some time ago)? A former wind tunnel mule?

Or, rather less remarkably, somebody just picked up a cheap V8 Supercar track day toy given these cars have been around for a while now (despite still being raced as a current model in the ATCC)?