The V-shaped wedge with the cutout on the left is used for V-mount (also called V-lock) batteries.
The URSA Studio Viewfinder uses a V-shaped wedge with the cutout on the right which is the same shape used in Sony VCT style mounting plates.
If you are just looking for a compatible V-shaped wedge that you could attach to other devices (but would fit the same quick release receiver mount), there are a few other companies that make these. For example:
https://www.shapewlb.com/delta-adapter/https://shop.dm-accessories.com/products/vct-wedgeBut the mounting hole patterns look different from the one built into the bottom of the Studio Viewfinder, so I doubt you could use either of those as a direct replacement. And judging from the design, mounting holes, and screws on the built-in wedge I'm guessing the Studio Viewfinder may be using a custom machined part. So I'd probably check with your local Blackmagic support office if you need to replace it.