msup-03.test

<<< mml
<?xml version="1.0" encoding="UTF-8"?>

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">  <msup>    <mn>2</mn>     <mn>3</mn>   </msup>   <mo>=</mo>   <msup>    <mn>2</mn>     <mrow>      <msup>        <mn>3</mn>         <mphantom>          <mi>fail</mi>
        </mphantom>       </msup>     </mrow>   </msup> </math>
>>> native
[ ESuper (ENumber "2") (ENumber "3")
, ESymbol Rel "="
, ESuper
    (ENumber "2")
    (ESuper (ENumber "3") (EPhantom (EIdentifier "fail")))
]