mspace-01.test

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

<math xmlns="http://www.w3.org/1998/Math/MathML" display="block">  <mtext>First line</mtext>
  <mspace linebreak="newline"></mspace>
  <mtext>Second line</mtext> </math>
>>> native
[ EText TextNormal "First line"
, ESpace (0 % 1)
, EText TextNormal "Second line"
]