Enclosure corner shelf. I have way more space in the tent than anticipated, and chose to use that space to hold sensors and other relatively still items as there is always the slight risk of something falling and hitting the printer.....

This is for the: Creality Enclosure - Large 700750900MM - https://www.amazon.ca/dp/B0CLVKF7YH
Although I would anticipate it would fit other enclosures with similar pole widths.