These are simple templates for sockets for Wago 221 clamps. They can easily be modified by adding screw holes, other attachment methods, inclusion in housings or simply glue them in place.
The wago clamps should fit very tightly and can only be removed by rotating them upwards with a good portion of force. You should hear a click, when they snap into position.
The template includes sockets for the 3 most used types 221-412 (2 terminals), 221-413 (3 terminals) and 221-415 (5 terminals).
The author hasn't provided the model origin yet.