HTML-CSS and SVG output: minimal height for mover base [was [TeX input] \quad has no height]
It seems real (La)TeX considers \quad
to have a height but the TeX input jax only produces an mspace with width.
An example (distilled from a journal article):
\widehat{\quad}: O \to Y
produces
<math display="block">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mspace width="1em" />
<mo>^<!-- ^ --></mo>
</mover>
</mrow>
<mo>:</mo>
<mi>O</mi>
<mo stretchy="false">→<!-- → --></mo>
<mi>Y</mi>
</math>
but the following is closer to rendering in real LaTeX:
<math display="block">
<mrow class="MJX-TeXAtom-ORD">
<mover>
<mspace width="1em" height="0.5em" />
<mo>^<!-- ^ --></mo>
</mover>
</mrow>
<mo>:</mo>
<mi>O</mi>
<mo stretchy="false">→<!-- → --></mo>
<mi>Y</mi>
</math>