value of \fboxsep is not preserved

[xworld21]

When outputting a \fbox, the value of \fboxsep is ignored. The end result is that every framed box has no padding at all in the default stylesheet – at a minimum, the default CSS could include the usual 3pt padding. Minimal example is

\documentclass{article}
\begin{document}
\fbox{box}
\end{document}

XML output

<para xml:id="p1">
  <p><text framecolor="black" framed="rectangle">box</text></p>
</para>

even though the value of \fboxsep is 3pt (set within LaTeX.pool.ltxml). Changing \fboxsep has no effect, it seems like the value just is not used.