This is a .3mf file preconfigured for use with PrusaSlicer to print your own two-color filament on a MK3.
The actual model is identical to the original two-color filament design, but scaled up to the largest size that can fit the MK3 build plate. The original design is a bit undersized and expects that you will need to increase your extrusion multiplier to compensate, but the scaled up version has the same cross-sectional area as round 1.75mm filament and prints great with the built in PrusaSlicer profiles.
The author remixed this model.