[latexrefman] Stretch the interword space in @var{text} across the entire @var{width}.

[Vincent Belaïche]

I have read this in node « \mbox & \makebox » and I am wondering
whether this is true for all scripts. Notably is that true for Arabic
where there is quite a lot of possible ligatures and you would expand
contract the words themselves, and not only the inter-word space.

What about also the microtype package …

  V.