This is a set of little trays that sit in the holes in the lower rear frame of the Seckit SK-Tank. Two of them have holes to pass cables through, and the third has recesses for two 10x10x29 bubble levels* at right angles to each other, making it easy to level your printer. The trays are perfect for hex keys, nozzles, or other doodads.
*https://www.amazon.com/gp/product/B09BPYB7T6
The author hasn't provided the model origin yet.