They literally don't. it's not in my manual and not in manual cheapest LG and GE machines that are currently available for sale
This screenshot is seems to be from manual of Frigidaire FDB520RHB or something similar that was discontinued 12 years ago or so.
Some of the programs of this dishwasher will heat water as needed, and in addition there is a button "hot wash".
showing manual of 20 years old machine today as proof for how machine should be operated it's just like arguing with todays doctor using 300 years old medical books.
things changed.