Please help with identifying a door/window in a render

There's an item in a render I did in 2019 that I can't find now, because I can't remember what it was.  Clever, right?

I'm trying to recreate this cover I did in Poser.  The hallway is Dubious Hallway, but I swapped out the door at the end for something that has that fancy arched window over the top.  The problem is, I don't seem to have the Poser file any more; I think it's still on the old PC, which doesn't boot up any more.  And even if I did, I've moved computers and rearranged my file structures now so when I can import old PZ3 files into DS, most of them just throw their hands up and "I'm not even going to bother looking."  (I've also lost a low table and a chaise/bench from another render because it won't try to find the files.)

I thought the door/window thing might be a DM model, but it's not theirs (that I can tell).  I do think it came from the Daz store though, since most of my content does.

So.  You guys are really good at finding things.  Does anyone recognise that window?

(Edit: this isn't the finished cover btw, with all the pokethrough and stuff, it just shows the window better...)