When the Prusa PSU quick-release is used, the pass-thru is useless and another hole in the enclosure to be closed.
This model covers the pass-thru hole from the inside. It is simply snapped between the PSU and the back panel over the pass-thru hole.
It fits from the length and design with this model: Original Prusa Enclosure - PSU Back Panel Gap Cover
The model is crated with FreeCAD 0.21.2.
The author remixed this model.
Remixed the lower part of the model to cover the pass-thru from inside the cover.