Sorry, but I actually wrote that sentence (not ML), and I disagree. The special nut that retains the cross-feed crank does have a slight effect on the total backlash in the cross-feed as tightening it removes the end float of the jam nut. But if you remove the special nut and turn the crank without pulling on the crank (which would pull it off of the cross feed screw), the cross feed will work just as it normally does, albeit a little sloppily. Also, there is no half-nut in the cross feed system. The only half nuts (AKA split-nuts) are the pair on the back side of the carriage apron that engage the lead screw to traverse the carriage under power.
However, I will change the sentence to read "The chip cover and the brass cross feed nut are removed." My original was perhaps a bit verbose.