I was building a LACK Enclosure for my Prusa MK3S printer and read that the power supply unit (PSU) should ideally be kept outside the enclousre as the electronics inside should not be exposed to high temperatures for long term.
I wanted to design and support for the frame after the PSU was removed (as the one from Prusa didn't fit the new black power supply shipped with my unit) and yet wanted the optoin of mounting the PSU back onto the frame should I decide to bring the printer somewhere.
So I designed 2 sockets on the frame and 2 square "hooks to slot into the sockets. The Square Hook is screwed onto the PSU using hte same holes used to mount the PSU previously.
I designed it to use the original screws and the spare nuts shipped with the prusa printer.
Also check out my Under Table Mount for the PSU which uses the same square hook.