texmath-0.9.4: tests/writers/mfrac-11.eqn
A over {B + C over {D + E over F}} = {hphantom 1 fwd 0 A} over {B + C over {D + E over {F fwd 0 hphantom 1}}}
A over {B + C over {D + E over F}} = {hphantom 1 fwd 0 A} over {B + C over {D + E over {F fwd 0 hphantom 1}}}