This is an upper mount to attach the Wedge RMU Mk3 to the right side of the Original Prusa Enclosure.
It uses the tool holder model for mounting. That uses:
See RMU Mk3 mount for Original Prusa Enclosure (lower) (https://www.printables.com/model/346741-rmu-mk3-mount-for-original-prusa-enclosure-lower/) for the corresponding lower mount.
The author remixed this model.