This is a holder for a nozzle brush which cleans an XL extruder on tool changes.
The original model is the adjustable brush holder here https://www.printables.com/model/462473/files
The remix supports these brushes (actually without a 3 mm screw): https://www.amazon.de/-/en/gp/product/B086JP3C45
The author remixed this model.
This is a remix of the adjustable brush holder. It has a hole diameter of 3.2 mm and a length (down to the counterbore step) of 27.5 mm. (The original is 3.6 mm and 25.5 mm.)