Arno Trautmann wrote:
> Hi,
> this is my first post to this list, and I hope, it’s not a faq.

Not sure there is a FAQ here: the topic varies.

> It’s already in the subject: Is LaTeX3 designed to work well with the
> TeX-successors XeTeX and LuaTeX? Is it compatible? 

Yes, works fine.

> Has the code to be
> re-written to take benefit of new features?

Not at the moment.  For XeTeX, I'm not sure there would be so much to do
(port fontspec, basically).  For LuaTeX, my impression is that LaTeX3
will not use any Lua features in the LaTeX kernel. There is already too
much work to do to get LaTeX3 finished as it is.
Joseph Wright