Gene, help me find something.
Look at the image please, specifically the little side mount.
What is this? Be nice to have a second camera on it....second small camera
It's on the Leofoto LS-284C tripod.
forum: Sony Cameras
The bracket looks like what is called a "magic arm", an adjustable, articulating arm. The female threads on the tripod appears to be something that comes with that particular tripod.
Here's a link to an articulating arm as an example.
Here is a link to the articulating arm I bought that comes with a clamp at one end. I use it to clamp onto a light stand but it would also clamp onto a tripod leg.