This mount was designed for the following barrel jack adapter: https://www.reichelt.de/de/en/dc-2-1-x-5-5-mm-socket-2-pin-terminal-block-2-part-delock-65423-p127464.html (2.1 mm (interior) x 5.5 mm (exterior) socket)
An M3x20 bolt and nut is used to secure the adapter on the mount. The mount then just clips onto the DIN-rail. The prints I did in PETG clipped onto the rail quite securely.
The author marked this model as their own original creation.