Based off the design of the Universal Grip (innie) from Mechanism (formerly known as Deckmate).
You can use this with a ¼-20 screw to add a mount point for the Mechanism ecosystem.
I personally use this to mount a portable monitor that is held by a telescoping tablet bracket onto a Mechanism Claw Grip that clamps onto my camera tripod.
The robust version adds additional walls around to help counter the weakness caused by layer lines. When I used the locking version of the Mechanism Outie (like you'd find on the GoPro Mount), it broke the lip off when it locked.
The author remixed this model.