This "clamp" is a component. It is used with webbing and a ratchet to create a complete corner-clamp system. Four of these clamp pieces go on the corners of a box or cabinet, and a ratchet draws them tight. I use a ratchet and strap originally meant as a tie-down for small truck cargo.
v2 seems to work pretty well. For larger pieces you might increase the size of the mating surfaces. Enjoy.
This work is placed explicitly in the public domain.
I printed this with PLA, 5 perimeters, and 15% infill. That seems okay ..
The author hasn't provided the model origin yet.