invChars.test

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

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mn></mn> 
  <mo></mo> 
  <mi></mi> 
  <mo>&#x2062;</mo> 
  <mn>&#x0009;</mn> 
  <mo>&#x2061;</mo> 
  <mtext> &#x200B;</mtext> </math>
>>> native
[ ENumber ""
, EMathOperator ""
, EIdentifier ""
, ESymbol Ord "\8290"
, ENumber ""
, ESymbol Ord "\8289"
, ESpace (0 % 1)
]