Leviton supplies a shelf bracket kit that spans half the width of the media enclosure. This version provides a shelf with brackets to cover 2/3rd the width of the enclosure for wider objects.

Printed with PETG, 0.4mm nozzle, 0.2mm layer height, 3 to 4 perimeters for strength, 30% GRID infill, painted supports as shown. If you want stiffer, then use PLA.

Update 2023-11-22: added regular sized shelf.