This is the bottom bracket for the Venetian blinds. The original is clear in colour and breaks at the angle. So I made one out of PLA and a little thicker stronger and stiffer.
So you have to install it by placing the blind slats in the midway/horizontal position and screwing the bracket in place as it doesn't flex like the original.
The bracket stops the Venetian blinds being blown around in the wind. or in this case swinging from side to side on as they are attached to a sliding wooden door.