Winterized, yes, but still definitely just an agricultural tractor.
Manon Ossevoort is not the first person to have traveled to the South Pole in a tractor. Sir Edmund Hillary did it in 1958. But Hillary was a professional adventurer, and it took him some two months to reach the pole from the coast. Osservoort, a professional actress, just did it in 17 days. Osservoort’s expedition was named Antarctica 2, in honor of Hillary, and was supported in a large part by Massy Ferguson, manufacturers of the tractor.
Temperatures would reach 56 degrees below zero (Celsius, although the scales are quite close at that temperature) and the trip would require 23-hour driving stretches. Quite a remarkable achievement.