msub1.test

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

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <msub>
    <mi>m</mi> 
    <mrow>
      <mn>1</mn> 
      <mo> &#x2063;</mo> 
      <mn>2</mn> 
    </mrow> 
  </msub> </math>
>>> native
[ ESub
    (EIdentifier "m")
    (EGrouped [ ENumber "1" , ESymbol Ord "\8291" , ENumber "2" ])
]