texmath-0.13.1.2: test/roundtrip/msup-05.native
[ ESuper (EIdentifier "x") (ENumber "3") , ESymbol Rel "=" , ESuper (EIdentifier "x") (ENumber "3") ]
[ ESuper (EIdentifier "x") (ENumber "3") , ESymbol Rel "=" , ESuper (EIdentifier "x") (ENumber "3") ]