Hinge for doors or panels to fill Tee-slot structures. Make doors or just use fixed as a stop for filler panel mounting or even paper or fabrics. First version so not fully tested, printed with supports, the first print freed up and operates well. It has a 'tension' mechanism so it 'snaps' in position. Opens 90 Degrees.
Hinge snaps free be pressing assembly down on a hard surface or squeeze it with some pliers.
Not tried the screw-lock or which screw will work best. Probably the stubby ones used for mounting Blum type hinges into particle board/Melamine.
I'll be working on this some more over the next few days.

Designed to work with the Vention system, need to see other profiles but here's the link for customizing it.
https://3dorchard.com/app/single/5dd98a5721acd30b264cd90e/5e56cb7e2638430b7f08769b

Makes a good pocket fidget thing as well

Hopefully the ThingiViewer will work soon.

I used the imported (pasted) 45MM Tee slot (dl STEP file from Vention.io) as my working template. Plan view, sketched the new profile in 2D with 1MM grid setting in Orchard to get the 'extrusion' profile.
Still in 2D mode, sketched onto the extrusion 'top', the 'crescent' shape. Extruded the crescent down and subtracted it from the main body.
Top mirrored the extrusion with the cutouts, fused the 2 pieces to create the curved slot. Dragged horizontal surfaces to suit my whims.
Made the actual crescent shape smaller for clearances (the rotating part). Reset it's axis to confirm clean rotation action, sketch tool to modify the stop and 'lock' elements. Position it midway for the print to ease freeing it.
Sketched the profile for cutting the attachment 'barbs' and extruded it. Subtracted it from the main extrusion.
For the screw hole, created a cylinder and tapered it, subtracted it from the extrusion. The order is important, do square cuts first, once rounded cuts or rounded edges come in, more modeling can get complicated.
The steps are visible on the Orchard tree.