I don't...think so? It looks like some kind of weird suspender tie thing; look at how it loops under her shirt as if it's attached to her pants.
I've honestly never seen anything like it before.
I thought i never saw it either, but looking at her official art closely... yeah it does look like some kinda suspender tie thing there. I thought she was having an open jacket.
The old hag ancient one have some... unique fashion statements.