texmath-0.13.2.1: test/roundtrip/mrow-02.native
[ ESuper (EIdentifier "x") (ENumber "2") , ESymbol Rel "=" , ESuper (EIdentifier "x") (ENumber "2") ]
[ ESuper (EIdentifier "x") (ENumber "2") , ESymbol Rel "=" , ESuper (EIdentifier "x") (ENumber "2") ]