Holley used to make them. They were the 4100 series. 4110 and 4111 I believe. As I said, they were spun off the old Autolite 4100 carburetors. Summit picked them up and Holley discontinued them. I THINK Holley makes them exclusively for Summit now. Here's the Original Autolite 4100. You can see strong similarities.
View attachment 1716275100
They were and still are pretty darn good carburetors. As you can imagine, they are not prone to leak very easily, as the main gasket is above fuel level. The Holley 4100 series was very similar, just like the Summit series you have. It's a good design. Makes for a nice street carburetor.