This is an Arca Swiss and 1-4" UNC compatible tripod mount for DJI Osmo Pocket Wireless adapter. The mount was designed to leave all the ports open and accessible.
Push a 1-4" UNC threaded insert into the bottom hole (using a soldering iron) if you want to use the mount with a tripod screw.
The author marked this model as their own original creation. Imported from Thingiverse.