It's a remix of @h19x51 SPD Pedal Plate, with some enhancements for problems that I found in my case. I liked the original for the really simple, easy-to-print, and robust design. But it was somewhat hard to remove, a tad too small, and too slippery. So I changed the following:
Except for the lever holes, the plate is symmetrical. But you may want to print one plate mirrored along the Y axis to produce one with the holes on the left.
I tested it with ASA. Might be a good choice due to weather+light resistance, but a harder and smoother filament might be a good idea. Not sure what a good choice might be.
Another future addition which might be nice would be a clip to store the pedals on the bike frame, so you always have them with you.
The author remixed this model.