The basic unit is a fitting that slips into the hex opening on the left Z axis pillar. This fitting can host a USB female connector, making it great for use as a way to mount a USB light “stick” with a gooseneck. From there a “shelfAdder” hosts a wedge fitting that can host a variety of holders for cell phones or the ThermPro temp/hygrometer. The “P” and “L” designations in the files indicate “Portrait” (vertical) or “Landscape” (horizontal) placement.
The model was done in FreeCAD and has a spreadsheet to allow for size adjustment.
The author hasn't provided the model origin yet.