texmath-0.9.4: tests/writers/mfrac-03.eqn
A over {B + C over {D + E over F}} = {A to {hphantom 0}} over {B + C over {D + E over {F from {hphantom 0}}}}
A over {B + C over {D + E over F}} = {A to {hphantom 0}} over {B + C over {D + E over {F from {hphantom 0}}}}