American Curl turns up in a homeowner's backyard as a stray

This is unusual. Perhaps very unusual. A user on the Reddit.com website has posted a video which you can see below of a domestic cat that they thought had a strange appearance. 

They said that the cat was very big with strange ears. I immediately, identified the cat as an American Curl which is a fairly rare purebred cat and certainly very rare if he or she behaves as a stray cat which appears to be the case in this instance. 

They're not normally large cat but standard-sized domestic cats with one exception to their regular appearance namely the ears that curl back due to a genetic mutation.

Here is an example of an American Curl show cat photographed by Helmi Flick years ago.

Photo: copyright Helmi Flick.

Note: the video below may eventually stop working. Sorry but I can't control its existence. CLICK ON THE EXPAND ICON BOTTOM-RIGHT TO SEE THE VIDEO FULL SCREEN.

What kind of cat is this? Stray cat moved into my back yard. Has huge paws/weird ears.
by u/ReindeerNo1893 in cats

This breed is meant to be very standard in appearance and they can be tabby cats or any other coat type. I suspect that a neighbour of this person owns this cat. 

And the cat has wandered into a neighbour's property as domestic cats do. It is also slightly unusual for a person to allow their fairly rare purebred cat to wander around outside without supervision.

American Curl turns up in a homeowner's backyard as a stray. Screenshot.

An alternative assessment would be that this is a non-purebred cat which happens by chance to carry the genetic mutation which cause the ears to curl back. 

This gives them the appearance of a purebred American Curl. You won't be able to tell the difference because, as mentioned, the American Curl is a very regular looking cat. There are no other outstanding features other than the ears.